Introduction

During the early childhood period (Sylva, 1997), children have their greatest capacity for learning (ECE). During this period, children learn through a variety of methods, including imitation and discovery (Barr et al., 1996; Nielsen, 2006). Neuroscience studies have also shown that this period is one of the most productive periods of learning and cognitive development in one’s life (Organisation for Economic Co-operation and Development [OECD], 2018). Learning and adapting to change is at its peak during early childhood (Levitt, 2009; OECD, 2018). Children’s foundational skills support the development of mental, affective, and social skills in later years (Bakken et al., 2017; Woolfolk and Perry, 2012). Children’s cognitive development is strongly influenced by the ECE period, which covers the period from birth to age five (Özbay Karlıdağ, 2021).

It is evident that children’s experiences during their early childhood play a crucial role in their learning and cognitive development (Ozbay Karlıdağ, 2021). There has been a growing body of research indicating that students in more enriched environments have higher cognitive abilities than their peers (Farah, 2017; Hair et al., 2015; Lugo-Gil, Tamis-Lemonda (2008); Tooley et al., 2021). Children’s skill development is positively affected by environments that facilitate learning opportunities and facilitate children’s responses (Gerdes et al., 2013). Consequently, improving the environmental conditions of children in their early childhood contributes to their cognitive development.

It is the goal of ECE to maximize the cognitive development of students and to prepare them for school life (OECD, 2018). ECE has evolved historically from its original designs, which emphasized childcare for working women rather than education (Kamerman, 2006). Today, ECE has evolved into a distinct field of practice with its own curriculum and materials. The structure and approaches to ECE, however, vary significantly between countries (Bertram et al., 2016; OECD, 2020).

ECE plays a critical role in ensuring equal educational opportunities for children (Green et al., 2021; Magnuson et al., 2004; The United Nations Children’s Fund [UNICEF], 2018). Providing all students with a qualified ECE will allow them to acquire the necessary skills to succeed in school, thereby minimizing future achievement gaps (Magnuson et al., 2004). ECE is extremely valuable for supporting disadvantaged students who require the boost provided by ECE (Burkam et al., 2004; Lee and Burkam, 2002). A variety of factors, including the level of education of parents, the importance they attribute to education, as well as the opportunities they offer their children, contribute to students’ academic performance (Lugo-Gil, Tamis-Lemonda, 2008). ECE, on the other hand, allows students to begin learning on equal ground by reducing the effects of these gaps between students (Tucker-Drob, 2012; Waldfogel, 2015). As a result, ECE attendance has considerable potential for mitigating the achievement gap between schools, which is a long-term problem within the Turkish education system (Suna et al., 2020, Ozer et al., 2021; Ozer, 2021; Suna and Ozer, 2022).

ECE plays an important role in reducing achievement gaps by developing skills that students acquire during the most critical developmental period in their lives. Early childhood is a critical period for the development of cognitive skills and social skills (Kington et al., 2013) that leads to positive outcomes in both of these areas in the long run. As a matter of fact, participation in ECE has beneficial effects that extend beyond increasing academic achievement through skill acquisition. It has also been shown that participation in ECE mitigates school dropout rates and negative student behaviors (Cortazar et al., 2020; Schindler et al., 2015). By providing students with early childhood skills and alleviating other negative behaviors, ECE prepares children for school life and contributes to a positive school climate.

There is a socioeconomic gap between students in the period before the onset of school, which is reflected in the opportunities available to children during this period. While socioeconomically advantaged families tend to provide their children with more educational and cultural opportunities, the opportunities available to children from disadvantaged families are quite limited (Easterbrook et al., 2023). By offering similar opportunities for skill development to all students, ECE contributes to the development of student achievement in preschool period by reducing achievement gaps from causing socioeconomic disparities (Slaby et al., 2005). In the Indonesia Early Childhood Education and Development project, which was conducted with the participation of over 3000 children, it has been demonstrated that the achievement gap between children from high-income and low-income families is mitigated on diverse aspects by participating in ECE (Jung and Hasan (2016)). In this era of increasing inequalities (Piketty, 2014), it is more important than ever to maintain policies that promote equality, such as ECE.

Additionally, ECE has an egalitarian impact on education as a whole beyond achievement gaps (Geoffroy et al., 2010; UNICEF, 2018). A significant number of benefits and long-term effects can be derived from investments in ECE (Barnett and Nores, 2012; Lynch and Vaghul, 2015; United Nations Educational, Scientific and Cultural Organization [UNESCO], 2015). ECE interventions cannot be compensated for or replaced by other investments in later years (Ozer et al., 2021). When students benefit from ECE, the likelihood of long-term low achievement and skill gaps decreases, along with the cost of not reaching their full potential (OECD, 2020; UNICEF, 2019). Therefore, ECE is widely supported by education stakeholders, who have made it universal in many countries and included it in the Global Goals for Sustainable Development (UNICEF, 2018). To achieve their long-term development goals, many developed and developing countries have stated that “every student should receive at least 1 year of qualified Early Childhood Education by 2030” (UNICEF, 2018). ECE has numerous benefits, but policies guiding its dissemination and universalization have not yet reached the target, and barriers and gaps exist among countries (Eurydice, 2009; Neuman and Powers, 2021; UNICEF, 2018).

As a result of its numerous and long-term contributions, ECE has become a key policy area for many educational systems (Navarro-Cruz and Luschei, 2018; OECD, 2019b; Papakosma, 2023b). There are, however, differences among countries in the approaches to the development of ECE (Bertram et al., 2016). In many European countries, ECE systems have been revamped since the 1990s. The promotion of ECE can be promoted in some countries by implementing large-scale projects and incentive policies, while in others approaches such as extending the age at which compulsory education begins can be employed (Bertram et al., 2016; Navarro-Cruz and Luschei, 2018; OECD, 2019b). The participation rate in ECE has increased in almost all OECD countries, but each country faces its own unique challenges. Major difference between the countries with a long history of ECE and others is the context and used of ECE policies. Specifically, European countries with long-term ECE policies use ECE as an effective mechanism for their educational, social, economic, and political agendas (Papakosma, 2023a). This means that ECE plays a broader role than childrens’ skill acquision and increasing their radiness towards school in these countries. These challenges also lead to unique policy implications for more effective ECE systems.

One of these challenges is to maintain high quality and participation in ECE through continued investment and policy commitment (Bertram et al., 2016; Nakajima et al., 2021). In this context, a constant investment is required to meet the needs of educational environments, to provide healthy school meals to students, and to provide teachers for schools. Alternatively, in countries that have universalized ECE long ago, there is a more systematic relationship between the various stages of ECE (primarily in the pre-three and ECE age groups). An important development area is to increase the coherence between ECE programs at different age levels and to plan for holistic development (Bertram et al., 2016). As well, ECE differs significantly across countries with respect to different types of institutions, educational programs, etc. to be continued with these approaches (OECD, 2019b). The provision of standards, while providing considerable resources, is necessary to ensure that this difference in quality does not become a new source of inequality. A further observation is that there are too limited national assessments for monitoring and providing standards (Bertram et al., 2016).

Despite a major focus on cognitive skills, the development of social and emotional skills is one of the most important benefits of ECE. The early years of a child’s life are a time of exploration, communication, and recognizing one’s needs and feelings (Eğitim Reformu Girişimi [ERG], 2016). When children are provided with a safe and inclusive educational environment during this period, they are more likely to become more self-confident, express themselves better, and be more willing to interact with other people (Schlotman, 2023). The learning process helps children develop problem-solving skills, acquire better control of their anger, form friendships, and make ethical and safe decisions (Aceves, 2023; Trelles-Astudillo and Santacruz-Correa, 2023). Consequently, students with inadequate social and emotional skills may higher rate of school dropout, repetation and behavior problems. Multiple studies have also demonstrated that ECE mitigates negative behavior in schools (Cortazar et al., 2020; Orri et al., 2019).

Furthermore, studies have shown that social and emotional skills acquired in ECE are equally important, as they serve as the foundation for future skills. The development of social and emotional skills during early childhood has been shown empirically to have a positive impact on well-being over time (OECD, 2020; Richter et al., 2019). Due to the fact that “well-being” has become one of the most important indicators of quality of life in the modern world, ECE is a critical part of ensuring a child’s development of social and emotional skills. Additionally, many contemporary ECE programs implemented around the world strive to enhance students’ social and emotional skills, in addition to the principles of Turkish ECE.

Recent research also relieves the great contribution of ECE to the labor market dynamics. ECE alleviates the need for special education and increases mothers’ well-being and participation in the labor market (Evans et al., 2021; Young et al., 2019). Considering the outcomes of ECE, it has a significant impact on the child and his family, especially in terms of labor market variables. A new child limits a woman’s employment opportunities due to the additional care responsibilities, thereby preventing gender equality in the labor market (Bongaarts et al., 2019; National Bureau of Economic Research [NBER], 2023). A baby’s birth reduces women’s chances of finding work by 14% in Denmark, but it is close to 50% in the Czech Republic (NBER, 2023). First of all, ECE enhances the participation of women in the labor market by reducing the amount of early care responsibilities that are primarily performed by women (European Commission, 2022; Hassani-Nezhad, 2020; OECD, 2018). Furthermore, depending on a woman’s socioeconomic status (SES), the impact of having children on her employment opportunities varies considerably. The most socioeconomically disadvantaged women who have children face the greatest employment barriers (Hermes et al., 2023). As an example, Germany has taken continuous measures to enhance ECE across the country in order to reduce parents’ employment difficulties since the mid-1990s (von der Leyen, 2008). Studies have shown that universalizing ECE contributes positively to parents’ employment opportunities and that this contribution is greatest among mothers from socioeconomically disadvantaged backgrounds (Hermes et al., 2023). Thus, the expansion of ECE also contributes to more equitable employment opportunities by reducing wage differences between genders as well as SES (European Commission, 2022).

Participation in ECE is correlated with labor market variables in a manner that is not solely confined to the active participation of parents in the labor market. Participating in ECE provides students with academic support that also contributes to a smooth transition to employment over the long term by increasing skill development (European Commission, 2022). There has been a great deal of research showing that public investments in ECE are the most effective means of increasing the quality of human capital and facilitating school-to-work the transition (European Commission, 2022; Hermes et al., 2023; Vandenbroeck et al., 2018). As an example, in a study examining the impact of the “Head Start Program”, an ECE program available to the public entirely in the United States, participants in the program experienced a significant increase in employment transition rates and hourly earnings (De Haan and Leuven, 2016). The sociologically important aspect of ECE is that these benefits are concentrated in the most socioeconomically disadvantaged groups (Goudeau et al., 2023). It is clear from the above that ECE contributes significantly to the employment prospects of both the participating children and their parents, particularly their mothers. Furthermore, focusing the contribution of ECE, especially on socioeconomically disadvantaged families, has a great potential for promoting equity.

Through these multidimensional benefits, children’s education period is extended, they display fewer negative behaviors such as school dropout and disciplinary problems, and they adapt to society more effectively as adults (e.g., with low crime rates and high citizenship skills) (Bakken et al., 2017; Garcia et al., (2020); Mitchell et al., 2008; Reynolds et al., 2018). Also, ECE facilitates students’ transition to higher education, thereby increasing their access to highly respected professions (European Commission, 2022; Reynolds et al., 2018). Therefore, students’ academic achievement may be enhanced by attending a qualified ECE program.

Despite the general consensus regarding the benefits of ECE for individuals and society, the relationship between ECE and educational outcomes remains to be explored. Although previous studies indicate that ECE education plays a positive role in academic achievement, this link can weaken over time (Barnett (1995); Gupta and Simonsen, 2015). Academic achievement and learning are complex concepts, and improving these aspects may not always produce tangible results. There are some studies that have indicated that there is no significant relationship (or an insignificant, nonlinear relationship) between ECE education and academic achievement (Gupta and Simonsen, 2015). In addition, meta-analyses have indicated that ECE programs can provide multiple benefits, although these benefits may not reach statistical significance (Tanner et al., 2015). The relationship between ECE attendance and its long-term association with academic achievement is thus of interest from an educational research perspective (Reynolds, et al., 2018). There is a strong association between ECE attendance and academic performance, and there is also evidence that the relationship may persist and wane over time (Nold et al., 2021; Suna and Ozer, 2022). For example, Campbell et al. (2002) and Reynolds et al., (2003) found that ECE attendees had higher academic and scholastic performance in their 20 s and 21 s, although the effect was not significantly greater than the effect of early years of education. By contrast, Nold et al. (2021) found that the relationship between academic performance and participation in ECE did not appear to be significant. As a result, despite the agreement that ECE provides students with significant academic and social skills and has a long-term impact on personal and societal outcomes (Cappelen et al., 2020; UNESCO, 2008), we still require further evidence for the relationship between academic performance indicators and attendance at ECE across various time periods.

Several factors may explain the relationship between ECE attendance and academic achievement, including the structure (e.g., education-oriented or care-oriented), curriculum, and duration of the program. Education systems monitor the relationship between ECE attendance and educational outcomes (Bauer and Schanzenbach, 2016; García et al., (2021); NBER, 2021; Taggart et al., 2015). Examples of such evaluations include the HEAD Start, Perry Preschool, and Abecedarian Projects, which in the 2010s targeted reaching 75% of children with ECE, as well as the Effective Pre-School, Primary and Secondary Education Project in the United Kingdom (Bauer and Schanzenbach, 2016; García et al., (2021); NBER, 2021; Taggart et al., 2015). It is in this context, both longitudinal research and large-scale studies can provide significant insights into the nature of the relationship between ECE participation and educational outcomes.

Literature review on ECE and academic achievement

A significant amount of research has been conducted on the relationship between ECE attendance and educational outcomes. Barnett (1995) conducted one of the most comprehensive studies on this topic. As well as large-scale projects such as Head Start, the long-term effects of small-scale ECE programs such as homeschooling programs were also examined. According to the study, participation in ECE is associated with academic achievement, improved cognitive skills, and decreased grade repetition. It has also been found that qualified ECE programs (low-sized classrooms, highly-trained teachers, and frequent feedback to students) have long-term benefits.

According to Currie and Thomas (1995), the “Head Start” program, which targeted socioeconomically disadvantaged students in the USA, had a significant effect on cognitive abilities. In both white and African-American children, participation in the program was significantly associated with higher academic achievement. This increase, however, weakened more rapidly among African-American students.

Gorey (2001) examined the long-term relationship between 35 ECE programs and various educational and social outcomes. According to the quasi-experimental study, children who received ECE had higher levels of intelligence and academic achievement. These findings indicate that these effects persist over a period of 5–10 years, and that 7–8 out of 10 children who receive ECE have better cognitive skills than the average child.

Campbell et al. (2002) examined the contributions of the Abecedarian project, which began in 1972 with a sample of 98% African-American children. After completing the program, students in the follow-up study (at the age of 21) showed significantly higher scores in mathematics, reading, and verbal intelligence. Students enrolled in the program also have an average education period of half a year longer than students not enrolled in the program, and the rates of employment and transition to higher education are significantly higher.

As a result of the Chicago Child-Parent Center Program, which was completed in the 1980s with the participation of more than 1500 students, Reynolds et al., (2003) evaluated the long-term effects of the program. A follow-up study (when the participants reached the age of 20) demonstrated that the students who were enrolled in the program had significantly greater scholastic abilities and reading skills than their peers. Furthermore, the study found that students participating in the program had a higher rate of high school completion and a longer average period of education.

During the High Scope Perry Preschool Education project, which began in 1962, Schweinhart et al. (2005) examined the characteristics of 123 African-American individuals. As participants in the program reach the age of 40, they perform better on standard assessments, and they are more likely to graduate from high school and find employment. As a result of education and employment advantages, participants’ lifetime earnings were estimated to be $150,000 higher, on average, according to the study.

Milligan (2012) examined the second-year educational outcomes of students enrolled in full-time ECE programs in the southern California region as compared to those enrolled in half-day programs. A sample of 208 students was used for this study, and the results indicated that there were no significant differences in basic numerical and verbal skills, including reading and mathematics, between students who participated in two different early childhood programs.

As a result of the central assessment made at the end of fourth grade, Cortazar (2015) found that Chilean students who received ECE had a higher academic achievement. The benefits of ECE have also been demonstrated to be significant, especially for students from lower and middle socioeconomic backgrounds.

In 310 villages in Indonesia, Jung and Hasan (2016) examined the impact of the “Early Childhood Education and Development” project on achievement gaps. Comparisons were made between the villages where the project was implemented and the villages where it was not implemented. In villages where the ECE program was implemented, achievement gaps between high- and low-income students were significantly lower than in other villages as a result of the study targeting 4-year-old students.

In its study, Nold et al. (2021) examined the relationship between the achievement criteria of the state-funded ECE program implemented in three states in the United States. The target group for this program was students in the lowest income bracket in South Dakota. In contrast to other studies, it was reported that students participating in ECE had higher academic achievement, but the difference between the two groups was not statistically significant.

The development of ECE and its relationship with academic achievement in Türkiye

The history of ECE dates back to the Ottoman Empire, long before the modern Turkish Republic (Türk, 2011). Students were provided with knowledge and skills that formed the basis of school life, including religious education, in these institutions, which spread primarily during the 17th century (Türk, 2011). Back then, the content and progress of ECE were quite different from what they are today. ECE programs similar to modern understanding developed during the Tanzimat period in the Ottoman era (Türk, 2011). Early in the twentieth century, educational institutions similar to kindergartens and kindergartens began to be established in the modern sense. Children were taught skills through games similar to those employed in ECE institutions in Europe during this period.

Over the course of the Republican period, primary education institutions were given long-term priority, and the opening of current ECE facilities occurred in the 1960s. Consequently, there is very limited access to ECE due to the concentration of educational investments and goals in primary education. During the early 1980s, when ECE had high enrollment rates in Europe, the 36–72 month enrollment rate in Türkiye was 1.9% (Er-Sabuncuoğlu and Diken, 2010). Until 1990–1991, this rate could only be raised to 5.1% (Er-Sabuncuoğlu and Diken, 2010). In 1992, the General Directorate of Early Childhood Education was established, which played a significant role in increasing the prevalence of ECE in Türkiye. The first findings of the General Directorate indicate that the physical infrastructure and the number of teachers were inadequate to disseminate education.

Since the beginning of the 2000s, ECE has gained importance and become more widespread, although it has only increased by 11% up to the present. As has been the case with other levels of education, investments in ECE have also increased significantly. Increasingly, targets for this level have been included in top policy documents, and the 2009 MoNE strategic plan set a goal of increasing schooling rates to 70%. A gradual increase in the number of kindergartens and nursery schools has been implemented in order to achieve these objectives (Ozer et al., 2023). Together with the World Bank, Türkiye developed projects to disseminate ECE (The World Bank, 2013). There is often a recommendation that should be included in compulsory education at least 1 year of ECE in the top policy documents. Despite all these initiatives, early childhood enrollment rates are at the lowest level among OECD countries by 2020 (OECD, 2022).

The Turkish education law expresses the four aims of ECE as follows (Tuğrul, 2018).

  1. 1.

    Fostering the development of children physically, mentally, and emotionally.

  2. 2.

    Ensuring that children are prepared for primary school.

  3. 3.

    Promoting an environment for disadvantaged children and families.

  4. 4.

    Supporting children learn Turkish correctly and fluently,

ECE programs are designed to meet these four objectives between the ages of 0 and 72 months. ECE is provided in Türkiye in nurseries between the ages of 0 and 36 months, and in kindergartens and nursery schools between the ages of 36 and 72 months. Various public and private institutions offer ECE from the nursery age (0–36 months) through kindergarten age (36–72 months). However, both public and private institutions offer early childhood programs developed by the Ministry of National Education. Therefore, all ECE institutions, whether public or private, offer the same educational program to students, providing an inter-institutional standard.

The Ministry of National Education (MoNE) launched the “Early Childhood Education Campaign” in 2021 with the objective of ensuring that all students receive at least 1 year of ECE. In the last one and a half years, the number of kindergartens in Türkiye has tripled (OECD, 2023; Ozer et al., 2023). As a result, the 5-year-old schooling rate was increased from 65% to 99%, and the 3–5-year-old schooling rate was increased from 43% to over 51%, ensuring that each student received at least 1 year of ECE.

Since many years, discussions regarding the expansion of ECE in Türkiye have been primarily concerned with reducing achievement gaps between schools and regions (Madra, 2017; The World Bank, 2013; Suna and Ozer, 2022). For many years, achievement gaps have been a major problem in Turkish education. According to the OECD, in 2003, when Türkiye participated in its first PISA cycle, it had the highest achievement gap between schools (between-schools variance). The achievement gap between schools in Türkiye remained above the OECD average (Schindler et al., 2015) despite improvements until 2018 PISA cycle. A number of national large-scale assessments have also demonstrated significant achievement gaps between regions and schools (Ebrar Yetkiner Özel et al., 2013; Ersan and Rodriguez, 2020; Gümüş and Atalmış, 2012; Türkkaş-Anasız et al., 2018; Yekta, 2005; Ozer, 2021). Socioeconomic gaps, school tracking practices, and differences in access to ECE are all factors that contribute to the achievement gap between schools and regions. In addition, compared to countries with similar performance, Türkiye has a high rate of students with socioeconomic disadvantages (OECD, 2019a). As mentioned in the previous section, ECE has significant benefits, particularly for underprivileged children. Therefore, the dissemination of this education is essential for building a more equitable educational system.

Compared to the global literature on ECE, there are relatively few studies based on data that examine the relationship between participation in ECE and educational outcomes in Türkiye. These studies examined the relationship between students’ performance in national and international large-scale and school assessments and their participation in ECE. In a recent study conducted by Anasız et al. (2018), there is a significant relationship between the ECE participation of students living in both rural and central regions in Muğla province, located in the southwestern part of Türkiye. The results presented in the study showed that 8th grade students attanded ECE had higher mean scores in large-scale assessments in all subgroups, including gender and urban-suburban. A follow-up study conducted 22 years after the intervention program (The Turkish Early Enrichment Project-TEEP) by Kagitcibasi et al. (2009) examined the effects of the program. In this study, education was provided to both mothers and children from 255 low-income families. After 22 years of research, it has been demonstrated that maternal education and ECE have a significant impact on academic and social skills as well as SES. In a study conducted by Akçay (2016), it was found that students who received Early Childhood Development (ECD) performed higher than their peers in all five Turkish language skills: writing, listening, speaking, and reading. A study by Kartal (2007) demonstrated that the Mother-Child Education model, which is one of the ECE models used in Türkiye, contributes to students’ cognitive development. The results of the study indicated that students participating in the ECE program in this model developed more numerical and verbal skills than their peers. In a recent study by Suna and Ozer (2022) examined the relationship between ECE attendance and academic achievement via international large-scale assessments. At both primary and secondary education levels, academic achievement and literacy levels of students participating in ECE programs are significantly higher. However, this relationship is stronger at the primary level. Furthermore, the results of a study by Erkan and Kırca (2010), including 170 children who participated in an ECE program in Ankara, showed that these children have higher levels of literacy and school readiness than their peers. Ağırdağ et al. (2015) showed via international large-scale data that ECE is associated with higher academic achievement, even when SES is statistically controlled.

There have also been studies conducted by non-governmental organizations on ECE and educational outcomes in Türkiye. Kaytaz (2005) examined the cost-benefit ratio of ECE and found that a one-unit investment in ECE could result in benefits of up to 6.37 units. With just a decrease in school dropout, 2.28 units of benefit can be produced for each unit of investment. The finding emphasized in studies by Kaytaz (2005), Madra (2017), and Suna and Ozer (2022) is that participation in ECE in Türkiye has a strong relationship with SES. The participation of children from higher socioeconomic backgrounds in ECE has been high for many years, even though there has been a marked improvement over time. As a result, the achievement gap based on differences in SES continues to widen.

Thus, studies examining the relationship between ECE and achievement indicators in Türkiye have many limitations. The studies were generally conducted with a limited number of student groups studying in certain regions using conventional sampling procedures. In spite of the fact that these studies present significant findings, they were not conducted with a sample selection that could be used to represent the situation in the relevant region. As part of the data collection process, student and teacher perceptions were often used to determine participation in ECE programs and achievement indicators. Further, there has been no study conducted that examines the relationship between ECE attendance and academic achievement from a variety of SES using representative data from a nationwide large-scale assessment. This study uses ECE attendance and large-scale national assessment data without sampling in order to provide highly representative findings regarding the relationship between ECE attendance and academic performance. Using national assessment data, preliminary findings are presented regarding the change in this relationship according to SES.

Theoretical framework

ECE has been found to be beneficial in light of recent advances in developmental psychology (Saracho, 2023). As a matter of theory, the neonatal and childhood periods, respectively, are the periods when children’s cognitive development potential and learning capacity are at highest level. There are a number of theories that confirm the long-term effects of ECE on children’s mental and physical health. These theories include: maturationist, constructivist, behaviorist, psychoanalytic, and ecological theories (Bradbury and Swailes, 2022; Saracho, 2023). According to developmental theories, the early childhood period is considered to be a period of breakage as well as a period with a high potential. There is also evidence that children who are not adequately supported, who are limited in their development, and who have experienced trauma experience many negative consequences (De Bellis and Zisk, 2014). As a result, it is expected that a well-structured ECE will enhance the cognitive capacity of children and promote their long-term success (Barnett, 1995).

The field of ECE has the potential to make a significant contribution to policy and social equality. A child’s participation in ECE may theoretically contribute to their support for school readiness, maximize their psychological and social potential, and reduce the long-term effects of the negative effects they experience (Barnett, 1995); Correia-Zanini et al., 2018). Through the dissemination of ECE in society, this multiple benefit can contribute to the reduction of inequalities. There is evidence that ECE can contribute to social justice by ensuring that children have equal opportunities and begin their school careers under the same conditions (Barnett, 1995).

A further dimension of the theoretical discussion of ECE is the evaluation of the right to benefit from the opportunities it provides for children. Children from high SES benefit more from ECE owing to the fact that participation is related to SES on a global scale, causing the existing inequalities to deepen (Chzhen et al., 2018; Magnuson et al., 2004). Thus, establishing policies that ensure that all children can benefit from ECE is a criterion and a human right (Woodhead, 2006).

Research findings from several countries have supported theoretical expectations regarding ECE’s contribution. However, due to the nature of education, assessing the medium and long-term contributions of ECE presents many challenges. In the first place, students have different educational experiences in primary school than in secondary school, thus making it difficult to determine the original contribution of ECE. Second, although there is consensus that ECE has many benefits, this contribution does not always result in significant improvements. A third consideration is that ECE programs vary in duration and content, so their relationship with educational outcomes may also vary. The importance of examining the relationship between ECE programs and educational outcomes and using the results to provide feedback is paramount in this context.

Early childhood theories indicate that enriched environments and standard educational processes will contribute significantly to cognitive skills during this period. There are several theorists who have developed different educational approaches, such as Montessori and Reggio, as well as Piaget, Vygotsky, and Erikson Experts who have developed different education approaches, such as Emilia have acknowledged the significance of qualified education offered during this period in strengthening and enhancing a child’s skills (Saracho, 2023). Therefore, regardless of how ECE is approached, whether through behaviorist, constructivist, sociocultural, or maturational perspectives, it can be expected to provide significant benefits to children.

It is noteworthy that although many studies confirm the positive aspects of theories and approaches to early childhood development from education, there are also studies in the literature that do not demonstrate the expected contribution (Gupta and Simonsen, 2015). The contrast can be explained by the fact that ECE varies significantly across countries and the impact of education is not always evident in academic performance.

As a result of its cultural norms, on the one hand, and infrastructure limitations, on the other, Türkiye is among those countries where ECE has become widely adopted only relatively recently. The findings of this study provide insight into the relationship between ECE and academic achievement, particularly in a country where ECE has long been replaced by family care and where ECE began later than most OECD countries. Furthermore, by utilizing data from more than five million students without any sampling, the study makes more generalizable predictions with respect to theoretical predictions.

Due to the prevalence of ECE increasing significantly in Türkiye in recent years, this study examines the relationship between ECE attendance and medium- and long-term educational outcomes. This study attempted to answer the following research questions.

  1. 1.

    Do early childhood education participation and medium-term academic achievement (upper-secondary education level) have a significant relationship?

  1. 2.

    Do early childhood education participation and long-term academic achievement (higher education level) have a significant relationship?

Method

Design

This study examines the relationship between participation in ECE and academic achievement and is classified as “causal-comparative ex post facto research”. Researchers are able to investigate the causes or reasons for the differences between groups within the scope of this approach (Salkind, 2010). A comparison of student groups was performed in this perspective in order to determine the relationship between ECE and academic achievement.

Research population

The study population consists of students who completed upper-secondary education between 2018–19 and 2020–21 and have taken the Turkish national higher education exam (YKS). During this period, the MoNE collected data on 5,625,798 students taking their higher education exams. A summary of the demographic characteristics of the population can be found in Table 1.

Table 1 Demographic Distribution of Students in the Population.
Full size table

Table 1 shows that ~83.85% of the students in the research population did not attend any ECE program, whereas 16.15% attended an ECE program. For the gender distribution of students who received and did not receive ECE, there is a fairly even distribution; however, parental education level is associated with attendance at ECE. Thus, ECE attendance is relatively higher among children whose parents graduated from higher education levels. Table 1 shows that ~40.38% of the mothers of ECE students hold a high school diploma or higher, while this rate is 24.95% for the mothers of non-ECE students. Furthermore, while 83.99% of ECE students come from families with a middle or higher income level, this rate is only 74.10% among students who do not receive ECE. Based on the demographic distribution of the population, it appears that ECE students generally enjoy some socioeconomic advantages, which is consistent with previous studies (Batyra, 2017; Ozer, 2021).

Data and analysis

Student population data was used with the permission of the MoNE Information Processing Department (Official Letter No: E-65968543-622.03-62841376). Based on the purpose of the study, both demographic variables and academic performance indicators of the student population was demanded by researchers. The demographic variables included provincial location of student, gender, education level of both parents, and average income level of family. These indicators were frequently used for determining students’ socieonomic status (Winkebly et al., 1992). Thus, MoNE Information Processing Department prepared the data with both academic performance indicators and demographic attributes through the e-school system. Based on the data collection procedure, ECE attendance data reflects the enrollment of both public and private ECE institutions without any distinction. As mentioned earlier, both public and private ECE institutions are obliged to consider common aims of Turkish ECE program and consider the national education program of ECE which constitutes a standard in diverse ECE institutions.

As the Ministry’s official data management platform, e-school platform included a significant range of data on students and their parents. Therefore, the data used in this study is a part of official student records of MoNE in Türkiye. The data of the study is prepared by MoNE Information Processing Department considering the design and official permission of the study and therefore, is not publicly available.

Data were derived primarily from the scores of students on two separate national large-scale assessments. We first examined the national large-scale assessment data from the High School Transition System (LGS), which was used during the transition to secondary education during 2017–2018. As LGS scores were obtained at the end of eighth grade, the LGS was considered a medium-term achievement test. Student take the LGS exams 8 years after the ECE programs in average.

Furthermore, this study examined academic achievement indicators measured by the Basic Proficiency Test (TYT) and Field Proficiency Test (AYT) during the transition to higher education. As an aptitude test, the TYT assesses students’ literacy skills, whereas the AYT measures their proficiency in a wide range of subjects. On the AYT, student performance is calculated in three dimensions: numerical, verbal, and equal weight. This approach allowed us to consider two different measures (TYT and AYT) of academic achievement over a long period of time. Students take TYT and AYT exams 12 years after the ECE programs in average.

The timespan of student population was as follows: the achievement scores and and ECE participation data of the student population was used in the study tracked through the official e-school system of MoNE. In this manner, the ECE participation data of the student population was dated between 2003 and 2008. The student population has taken the central examination for upper-secondary education (medium-term achievement) between 2014 and 2016. Lastly, they have taken the central assessment for higher education (long-term achievement) between 2018 and 2020. Therefore, diverse data points (ECE participation, medium- and long-term achievement) of same student population was used for analyses.

The results of the validity and reliability from LGS (central assessment for transition to upper secondary education), and TYT and AYT (central assessments for transition to higher education) were as in Table 2 (OSYM). The study considered the interval of 2018–2020 for higher education examination based on the increased participation, with a consistency of central examination system. This interval has a potential to maximize the generalizability of the results and minimize the differences between frequent changes in examination systems towards higher education.

Table 2 Psychometric Properties of Assessments Tools.
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As seen in Table 2, the reliability and validity results of the assessments tools for central examinations were above the criteria for high-stake assessments (Cronbach, 1960).

Due to the nature of the data, we focused on the differences in group mean scores of academic examinations (LGS, TYT, and AYT, respectively) in the study to examine the relationship between participation in ECE and academic achievement. Statistical significance was applied in this context to demonstrate that differences between groups are likely due to chance or to a factor of interest - in this instance, ECE participation. If there is a significant difference in means between two groups (ECE participants and ECE non-participants), then this may be due to the factor of interest (ECE participation). To gain a deeper understanding of the strength of this relationship, we conducted ANOVA and effect size analyses. Thus, these analyses also provide evidence that the relationship is dominant beyond its significance. Since the difference in means tends to be significant when the sample size or number of participants is large (Tabacknick and Fidell, 2013), this is particularly important.

One-way analysis of variance (ANOVA) was used to compare the mean scores of students who attended and did not attend ECE in all transition assessments (LGS, TYT, and AYT). ANOVA allows researchers to analyze the statistical significance of differences in mean scores with releasing diverse indicators for effect size (Tabacknick and Fidell, 2013). Partial-eta square coefficients were also used to interpret comparisons about the strength of relationships between assessments. As part of this study, several long-term educational performance indicators were also incorporated, including the percentage of students placed in higher education institutions, the most prestigious careers, formal higher education programs, and the top preferences among higher education programs. Next, student placement rates in university programs were compared between students who attended early childhood and those who did not.

In a recent study conducted by Sunar (2015), the “most respected” professions in Türkiye were identified. Among the most respected professions were physicians (medical faculty); attorneys, judges, and prosecutors (law faculty); and dentists (dental faculty). Finally, the SES of the students was determined by the education level of their mothers and fathers and their family income. The family income represents the position of total family income compared to minimum wage in Türkiye considering students’ and teachers’ opinions. On this manner, the family income mostly represents the comparable position of total family income level across minimum wage in Türkiye based on the student and teacher opinions. E-school system did not use standard and objective levels of income, it rather reflects subjective but commonly agreed position of income. Despite the fact that the family income may change in time, the most recent data about the income is considered. Table 3 presents the scoring metrics used to measure socioeconomic characteristics.

Table 3 Criteria and scores for determining socioeconomic statusa.
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When determining a student’s SES, parental education levels were evaluated separately. Thus, each student’s SES varied from 3 to 15. A cumulative frequency analysis of SES scores determined that ~33% of the students were classified as “low,” 70% were classified as “medium,” and the remaining students scored above the previous two levels were categorized as “high.” Due to the fact that this study used student population data, statistical tests were not conducted to determine the significance of differences in mean scores or ratios between subjects. The purpose of these tests was only to examine the change in the relationship between early childhood attendance and academic achievement, in case major socioeconomic data were missing.

Results

The relationship between attendance at ECE and academic achievement in the transition to upper secondary and higher education

Figure 1 illustrates the relationship between ECE participation and students’ achievement during the transition to upper secondary and higher education.

Fig. 1
figure 1

Average Scores in Transition to Upper Secondary- and Higher Education by Pre-school Education Attendance.

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The relationship between ECE attendance and academic performance in the transition to secondary education can be seen in Fig. 1. Compared to students who did not attend early childhood, students who attended early childhood had a mean score that was 35 points higher. Based on this gap, it can be concluded that ECE attendance has a significant but low association with medium-term academic achievement (η2 = 0.03). Therefore, early childhood students perform significantly better in large-scale assessments after 8 years of schooling than their peers who did not receive an ECE.

Compared to students’ performance in the transition to upper-secondary education, the relationship between their academic performance and ECE attendance is weaker in the transition to higher education. Students who received ECE have higher mean scores on the TYT (a general aptitude test), but the partial eta-square coefficient indicates that this relationship is significant but low (η2 = 0.01). A quite correlation was found between students who participated in early childhood and higher mean scores on the AYT (a proficiency test covering diverse subject areas) (η2 < =0.01). AYT-verbal mean scores between students who attended ECE and those who did not are negligible. Attending ECE is associated with a partial increase in academic performance during the transition to higher education. There is, however, a need for further investigation to examine the relationship between ECE and aspects of the transition to higher education.

Attendance at early childhood education and higher education placement rates

Figure 2 reveals the relationship between ECE attendance and student placement rates in all higher education programs, as well as in highly respected higher education programs.

Fig. 2
figure 2

The Relationship between Pre-School Education Attendance and Placement Rates in All Higher Education Programs and Higher Education Programs with High Reputation.

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When all higher education programs are considered, the placement rates for early childhood and non-early childhood students are very close. It should be noted, however, that when higher education programs are categorized and grouped, ECE makes a significant contribution to the transition to highly prestigious programs. A higher percentage of students with ECE are placed in highly prestigious programs, such as medical, dental, and law schools. Based on the findings in Fig. 2, ECE attendance plays an insignificant role in academic performance when transitioning to a higher education program directly, but plays a significant role in access to highly prestigious programs.

As shown in Fig. 3, the types of higher education programs in which students are placed vary based on their attendance at ECE.

Fig. 3
figure 3

Types of Higher Education Programs and Pre-School Education Attendance.

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Based on the Fig. 3, students’ choice of higher education program is related to their attendance at ECE. When comparing the two groups, it is evident that students who did not attend ECE significantly more likely to participate in open education programs and associate degree programs. The participation rate in formal higher education programs is higher among ECE graduates, with an ~10% gap. Therefore, despite the close relationship between the transition rates of both student groups to higher education, ECE participation increases the likelihood of placement in formal higher education.

According to Fig. 4, early childhood attendance is associated with a preference for higher education placement.

Fig. 4
figure 4

Preference of Students towards Higher Education Programs according to Pre-School Education Attendance.

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Figure 4 illustrates the significant differences between the two groups of students participating in higher education programs in terms of their first choice and top five preferences. ECE students are more likely to be placed in the top five preferences than the rest of the population, with the difference ranging from 1% to 4%. In this context, ECE students are consistently more likely to be placed in their primary preferences. Based on this study, ECE attendance is associated with an increased likelihood of placement in the program of a student’s primary choices. It is thus evident that ECE affects not only the type of higher education programs that students enroll in, but also the rate of placement in highly prestigious programs and the primary preferences of students.

The relationship between early childhood attendance and student achievement according to socioeconomic status

Based on the SES of students, Fig. 5 illustrates the relationship between early childhood attendance and academic achievement.

Fig. 5
figure 5

Mean Score Differences from the Transition to Secondary Education (LGS) and Higher Education (TYT) Exams by Student Socioeconomic Status.

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As shown in Fig. 5, the difference between LGS mean scores (transition to upper-secondary education) of students from different socioeconomic backgrounds is significantly influenced by early childhood attendance. As compared to those who did not attend ECE, the difference between scores of students from low and middle SES and the mean score (−0.17 SD for low SES, 0.02 SD for medium SES) was significantly larger among students who attended ECE (−0.41 SD for low SES, 0.24 SD for medium SES). By bringing low- and middle-income students’ performance closer to the mean, participation in ECE education contributes significantly to their achievement on upper-secondary education transition exams. As a result, students with high SES tend to achieve better than those who do not attend ECE. As a result, the gap between the SES groups in the transition to higher education has narrowed. In this level, there is a small difference between the mean scores of low- and middle-SES students and the overall mean, demonstrating that ECE is only beneficial to students with high SES. Accordingly, ECE participation plays a much greater role in transitioning to secondary education than in transitioning to higher education for all socioeconomic groups.

Discussion and conclusion

In this study, we examine the medium- and long-term relationship between participation in ECE and academic achievement in Türkiye. As an example of the multiple contributions of ECE, Türkiye is an important case study. There is, in fact, a high achievement gap between students in Türkiye, and a chronic achievement gap between schools (OECD, 2019a; Mullis et al., 2020; Ozer and Suna, 2022; Ozer, 2023), as well as a significantly lower rate of ECE than the average for the OECD (OECD, 2023). In addition, Turkish ECE began to become widespread late due to cultural norms. Due to the fact that ECE is not part of compulsory education in Turkish education system and the ECE skills acquired by the family. As a result, ECE is partially under-resourced and under-represented (AÇEV, 2017; Suna and Ozer, 2022). Additionally, participation in ECE has been significantly related to SES for many years (AÇEV 2017; Ozer et al., 2021; Suna and Ozer, 2022). It is clear probable that this link has made students who have already benefited from socioeconomic advantages more advantageous and widened the achievement gap between SES groups.

Because of these problems, the expansion of ECE in Türkiye is in a critical position. It is important to note that increasing access to ECE can alleviate student- and school-level achievement gaps as well as contribute to the development of a more egalitarian education system in Türkiye. In spite of all these advantages, major steps towards expansion of ECE only began to be taken in 2010 and later. While ECE plays an important role for a more egalitarian education system in Türkiye, there has been little research on the relationship between participation in ECE and educational outcomes. Literature has primarily examined the contributions of ECE programs as part of projects and at the regional level. Additionally, research on the contributions of ECE to educational outcomes from diverse SES groups is even more limited. In view of this, there is a need to examine in a holistic manner the relationship between ECE and educational outcomes. An important aspect of this study is that it provides preliminary results regarding the relationship between ECE participation and student achievement across a wide student population in Türkiye.

Since the limited literature in Turkish focuses almost exclusively on short-term achievement (Anasız et al., 2018; Ağırdağ et al., 2015; Erkan and Kırca, 2010; Kartal, 2007; Suna and Ozer, 2022), evidence regarding the relationship between ECE attendance and academic achievement is even more important in this country. Despite the consensus that ECE programs can provide significant long-term benefits, this has not been investigated in Türkiye using a representative data set. Furthermore, the higher education system exhibits structurally distinct characteristics in comparison to most of the systems found in the OECD and EU areas. Even though higher education has significantly expanded in the last 20 years in Türkiye, a significant number of programs are conducted online. This provides students with the opportunity to be competitive while transitioning to a formal higher education program. Secondly, students are generally challenged to perform at their best in order to gain admission to prestigious higher educational institutions in order to obtain better employment and educational opportunities. We therefore reviewed a range of indicators in order to make a comprehensive and adequate assessment of the relationship between long-term attendance at ECE and academic performance.

A prominent finding of this study is that ECE-attended students are more likely to transition to secondary education (medium-term achievement) and higher education (long-term achievement) than students who do not attend ECE programs. The results of the central examination in Türkiye indicate that students who attended ECE were significantly more likely to achieve higher average scores, particularly during the transition to secondary education (8th grade). The results obtained are in agreement with those described by Suna and Ozer (2022), Reynolds et al. (2003), and Kağıtçıbaşı et al. (2009). Nold et al. (2021) also indicate that although ECE continues to have a positive relationship with academic achievement, the relationship weakens over time. Furthermore, the results of the national central examination on the relationship between ECE and academic performance are consistent with findings from large-scale international studies (Ağırdağ et al., 2015; Suna and Ozer, 2022).

In this study, a comprehensive set of indicators was used to examine the relationship between ECE attendance and achievement in transition to higher education. Several factors are responsible for this, including the structure of the Turkish higher education transition system. Unlike many other countries, Türkiye conducts a central examination for the admission of students to higher education institutions. Students can, however, be placed in higher education programs with a wide range of scores, even though this arrangement allows them to compare their performance on a similar scale. Thus, in addition to the score obtained on the central examination, the rate of placement into higher education programs is considered as another indicator. Türkiye also has a unique feature in that a relatively high percentage of students who are placed in higher education institutions participate in distance education programs (Yurdakul et al., 2021). As of 2018, ~54–56% of students enrolled in all higher education programs will receive their education through distance education programs (Yurdakul et al., 2021). Therefore, in addition to the assessment scores of students transitioning to higher education and the rates of placement in higher education programs, we also evaluated the placement rates in face-to-face higher education programs and prestigious higher education programs.

According to the study findings, ECE programs make a significant contribution to participation in face-to-face and prestigious higher education programs. These findings are similar to those of Campbell et al. (2002) regarding the contribution of ECE to transitioning to higher education programs and prestigious professions. In Türkiye, ECE attendance is likely to contribute significantly to the transition to employment, since higher education is the most advantageous educational level (Yurdakul et al., 2021). The study does not provide direct evidence on this issue; however, van Belle (2016) and OECD (2020) have demonstrated that indirect contributions have been made to the development of the economy.

These findings also provide further evidence about the contribution of ECE attendance to academic achievement in a country with a late dissemination of ECE. Additionally, we found that the relationship between academic achievement and ECE attendance is stronger on a medium-term basis, but it remains significant on a long-term basis as well. This result indicates that ECE attendance may contribute to academic achievement after an average of 12 years of attendance. Thus, our findings are in coherence with insights of ECE and ECD for both medium-term and long-term basis.

The contribution of ECE attendance varies according to SES. A number of studies have indicated that ECE has a particularly positive effect on socioeconomically disadvantaged children (Bendini and Devercelli, 2022; Campbell et al. (2002); Madra, 2017; Magnuson and Duncan, 2016; OECD, 2020). The results of this study indicated that disadvantaged students who attended ECE achieved closer to average scores than their peers who did not attend ECE. Furthermore, this contribution is also observed among students from middle socioeconomic backgrounds. The importance of ECE in Türkiye is particularly important for students from disadvantaged backgrounds. The contribution has a particular relevance in Türkiye, where the number of disadvantaged students among the population of this age group is relatively high (OECD, 2019a). Accordingly, the results of the study indicate that participation in ECE can have a significant impact on reducing achievement gaps.

Furthermore, the findings of the last study support ECE theories in which the benefits of ECE are also highlighted towards children from disadvantaged backgrounds. Again, our results confirm earlier findings and expectations (Li and Lei, 2023; Vandenbroeck et al., 2018) that ECE attendance is significantly more beneficial to socioeconomically disadvantaged children. Our findings indicate that students with disadvantages are more likely to benefit from ECE attendance than their more advantaged counterparts. ECE’s theoretical role in reducing achievement gaps between schools and groups within society can also be supported by these findings.

As reported in the global literature, ECE has long-term and medium-term contributions in Türkiye. A unique aspect of this study is that it uses comparable national central examination data across all regions, examines medium- and long-term achievement, and presents preliminary findings regarding how the relationship studied varies according to SES. This study highlights the importance of expanding ECE and ensuring its accessibility, particularly for disadvantaged groups of students. Thus, the “Early Childhood Education Campaign” launched in Türkiye in 2021 is of the utmost importance from this perspective (Ozer et al., 2023). Monitoring student outcomes in a similar manner to Head Start and Perry Early childhood programs in the international literature will contribute significantly to the understanding of this mobilization.

Limitations

The study was conducted on over 5.6 million students who took university exams in Türkiye within the past 3 years without employing a sampling methodology. Even though this feature enhances the generalizability of the study’s results, the group consists of only students who took the university exam within the last 3 years, and the demographic information used in the study does not include students who are not registered in the system, limiting its generalizability. Accordingly, the study focuses on students who have taken the university exam in Türkiye between 2018 and 2020 and whose demographic data are complete in the e-school system. The study did not consider the type (school-based or home-based) and duration (from 1 to 3 years) of ECE when examining the relationship between attendance and achievement. In Türkiye, ECE is primarily provided in formal settings within schools, although home-based programs such as mother-child education are also available. Similarly, the duration of education for participants in ECE varies between 1 and 3 years. As a result, the study does not present specific findings regarding the type and duration of ECE. The SES of the students was also calculated based on the educational status of the parents and the family income status of the family. In light of the limited variety of data available, SES was determined by three variables, which can be calculated based upon more comprehensive variables in the literature.

Implications and suggestions

According to research findings, ECE in Türkiye has a positive impact on students’ educational outcomes in the middle and long term. Since the said relationship, although partially weak, continues to exist in a consistent manner, it highlights the importance of spreading ECE. The strengthening of the necessary mechanisms to increase the participation rate of 3–5 year olds in ECE in Türkiye will make a significant contribution to this cause. Based on the findings of the study, ECE theories have shown tangible results among a large population of students. Furthermore, it is necessary to increase the number of controlled and experimental studies focusing on the relationship between ECE programs and educational outcomes in Türkiye.