Investigating teachers’ use of literacy-infused science strategies: A mixed methods study

The 2019 science results from the National Assessment of Educational Progress showed that 8th-grade students, especially economically challenged and emergent bilingual students, made few gains in science and reading achievement. Researchers have found that scientific language may be a significant barrier to student comprehension. Researchers have advocated for integrating effective literacy strategies into the science curriculum to assist students in science and reading outcomes. We investigated the enactment of literacy-infused science strategies of a group of participating seventh-grade science teachers in a federally funded project following monthly virtual professional development sessions. Results indicated that teachers self-reported an overall increase in their use of literacy-infused science strategies after participating in monthly literacy-infused virtual professional development.


Introduction
Between 2009 and 2019, differences in achievement in K-12 science and reading between mainstream and at-risk students-such as economically challenged (EC) and emergent bilingual learners (EB) (formerly English Learners)-have remained unchanged [1,2].The most recent national science achievement scores report was in 2019 and included a disproportionate representation of eighth-grade ECs and EBs among those meeting the minimum standard.According to the report, only 52% of EC students and only 19% of EB students met or exceeded the cutoff score to demonstrate a basic understanding of science concepts and processes [2].Conversely, 81% of non-EC students and 71% of non-EB students met or exceeded the same standard.Scores among eighth graders on the 2019 National Assessment of Educational Progress (NAEP) reading assessment were similar to those on the science assessment.While only 60% of EC and 28% of EB students met or exceeded the standard cutoff representing a basic understanding of reading concepts and skills, 83% of non-EC and 76% of non-EB met or exceeded the same minimum standard.Due to the effects of poverty, EBs and ECs are at greater academic and developmental risk [3,4] and have lower degrees of social competence [5,6].The detrimental impact of a wide achievement gap for these vulnerable student populations warrants more equitable targeted interventions.

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A Framework for K-12 Science Education [7] posits that engaging students in equitable opportunities to participate in science practices (e.g., asking questions, collecting and analyzing data, constructing explanations, evidence-based argumentation) and providing quality learning environments (e.g., space, resources, and supportive teachers) are keys to equitable science education practice.The Texas Education Agency (TEA) recognizes the importance of practical resources that could help teachers build students' English proficiency and engagement in school [8].Based on 2018-2019 Public Education Information Management System data, EBs account for 20% of Texas public school system students who would benefit from equitable teaching practices [9].Integrating literacy-building strategies into content, such as science, promotes EBs' academic achievement [10,11].Language and content integration can include explicit instruction in literacy components (e.g., phonemic awareness), along with academic language development [10,[12][13][14], reading in content areas [15][16][17][18][19], and writing [20][21][22].The potential benefits of literacy-building activities and experiences to EC and EB students in content areas like science necessitate an investment in teacher professional development (PD) emphasizing language-development strategies for science teachers.This study contributes to that need by investigating the integration of literacy strategies into the science curriculum to benefit EC students, inclusive of EBs.
One of the earliest studies to evaluate the impact of science and literacy integration on linguistically diverse students was by Lee et al. [23].The study's teachers participated in a four-day PD that promoted the incorporation of English language and literacy development into their science instruction.Lee et al. [23] found that the intervention produced statistically significant gains in science and literacy achievement for elementary students, especially among fourth-grade students who had received 2 years of intervention compared to third-grade students who only received 1 year of treatment.Teachers who participated in the study indicated they were more comfortable integrating literacy strategies into their science lessons and affirmed their importance for EBs.
Professional development (PD) is an essential component in the ongoing learning of educators and should impact student achievement by advancing the knowledge and skills of classroom teachers [24].PD provided through online platforms has been described using a variety of terms.Fishman et al. [25] referred to online PD as any activity taking place over the internet and can be further defined by the tools utilized and interactions between participants.Synchronous PD allows teachers to interact with instructors and other participants in real-time, while asynchronous PD enables participants to interact with materials at their own pace [26].Tong et al. [27] defined three virtual PD delivery formats as synchronous with a facilitator, asynchronous with a facilitator, and asynchronous without a facilitator.Each nuanced approach to providing PD through online platforms will be described as virtual PD (VPD) throughout the paper.The flexibility of VPD allows year-round access to information and resources [27], which can assist rural communities that have traditionally had fewer PD opportunities and resources [28][29][30].For VPD to be effective, it must be "grounded in theory which informs practice, has willing participation, has sustainability, and allows for interactivity and interaction" [31].
While integrating literacy into the science curriculum has been broadly investigated at the elementary level [18,23,32,33], few studies examine the benefits of integrating literacy at the secondary level-particularly on EC and EB students [16,[34][35][36][37].This study aims to investigate the use of literacy-infused science (LIS) strategies among a group of seventhgrade science teachers after participating in virtual professional development (VPD).

Literacy-infused science as a conceptual framework
Three lines of research concurrently emerged under the banner of literacy-integrated science.Lee et al. [23] have spearheaded efforts to understand academic scientific language development among linguistically diverse students.Their work builds on a foundation of home language (culturally relevant vernacular and grammar) to develop academic scientific literacy [23, 38, see also 39].Simultaneously researchers such as Girod and Twyman [32] used literacy-integrated science to describe their exploratory work analyzing naturalistic uses of reading, writing, and language to trace early academic scientific literacy development among second graders.A more robust line of research under the banner of literacy-integrated science has focused on one to two specific aspects of literacy science integration (e.g., strategies like the use of reading partners [18]; reading as a literacy domain, [16,19,40]; vocabulary development [41]; vocabulary and sentence frames [42]; writing as a literacy domain [43]. The literacy-infused science (LIS) framework is distinct from other studies that utilize literacy-integrated science as it incorporates all four literacy domains into all aspects of science learning experiences-inclusive of more than merely scientific inquiry (e.g., vocabulary development, scientific writing including claims, evidence, and reasoning statements, reading to learn through expository texts, science discourse) (Fig. 1). 1 3

Literacy-infused science
Exploring the role of written and oral language in science is a crucial requirement for developing scientifically literate students [7,[44][45][46][47].The language of science traditionally presented in classrooms often poses comprehension challenges for students, especially EBs [15].Science vocabulary frequently differs from everyday conversations or may take on new meanings in the classroom [46,48].Additionally, new scientific discoveries mean that the field maintains a growing catalog of specialized terms, and this specialized language allows scientists to share their work with others through conversation and debate as well as written and published texts.
Teachers can assist students in their science content knowledge and literacy development by using effective strategies focused on scientific language acquisition [49,50].Research has shown that incorporating moderate amounts of scientific reading into the science curriculum positively affected students' science achievement [16,51].Students who received integrated science and literacy instruction increased their science content knowledge and reading achievement [10,52].The purpose of LIS is to assist students in developing their listening, speaking, reading, and writing academic language skills by incorporating English language and literacy development activities into the content curriculum.We present LIS strategies in the following sections to have demonstrable evidence for equitable practices that benefit EBs.

Speaking strategies
Traditional teacher questioning strategies often use the Initiation-Response-Evaluation (IRE) model, which focuses on teacher-controlled talk with limited student involvement [53][54][55][56].Limitations of the IRE model includes inadequate opportunities for students to practice language skills [57] and decreased communicative competence [58].Schroeder et al. 's [59] meta-analysis revealed that questioning strategies, including wait time, question frequency, use of higherlevel questioning, and comprehension questions, positively affected student science achievement.
During whole-group instruction, engaging all students in class discussion is essential to academic achievement [60,61] and can help students clarify their thinking and develop verbal reasoning proficiency [50,62].One way to achieve this is by using engaging questioning strategies which we define as the use of wait time, response opportunities, and specific content feedback.According to research by Rowe [63], when teachers allow a brief pause of 3-5 s after posing a question and after students respond, the quantity and quality of student responses improve, and student confidence is boosted.Opportunities, including think-pair-share, choral response, or displaying responses on personal whiteboards, engage all students, including those with disabilities [60,64,65].Teachers who carefully plan student feedback can increase student participation and the quality of student responses [66], especially when feedback contains specific details related to the content or task [67].In addition to engaging questioning strategies, teachers should provide speaking and writing opportunities that allow students to practice using academic language [68].Language fluency can be improved during discussions by encouraging students to respond to questions in complete sentences and whole phrases [69].

Reading strategies
Science courses rely heavily on informational or expository text to disseminate content to students.Expository text structures and features provide the reader with valuable tools to find and organize new information about a topic [74,75].Teachers can help students develop these tools by focusing on support in three phases: before, during, and after reading expository text.Before reading an expository text, students should be given an overall awareness of the text by previewing key features such as titles, headings, and vocabulary [17,76].Students may also need to work through decoding and practicing the pronunciation of challenging words [69].Strategic pre-reading supports can increase EB students' and struggling readers' confidence, accuracy, and comprehension [14].During reading strategies include using reading partners, which can create a safe environment, build reading fluency, and promote discussions between students, particularly with EBs and struggling readers [17,77].Reading partners can be operationalized by: (a) pairing students with a peer who has stronger reading skills [78]; (b) alternating roles from the student who reads aloud to one who is engaged in listening to their partner and asking questions about the text [77]; and (c) frees up teachers to support multiple learners and small groups in the classroom [18].After reading, comprehension of expository text is improved by completing graphic organizers [79] and utilizing text evidence to answer questions while participating in class discussions [75].

Writing strategies
Writing in the science classroom teaches students to communicate with a broader audience, internalize the content, organize, and clarify ideas [80][81][82].Students who employ writing to explain their ideas are engaged in reflection and reasoning, which can lead to a better grasp of science content than students who use writing only to summarize what they have learned [83].To help develop their writing skills, students should be shown how to transform ideas into text, construct sentences, respond to an audience, and revise drafts [84].Developing confident writers requires various strategies, including varied writing opportunities, writing scaffolds, and peer-review and sharing opportunities.
Effective science teachers encourage students to think like scientists through varied writing opportunities that promote scientific learning [11], including narratives, lab reports, the claim, evidence, and reasoning framework, and the use of science notebooks or journals [11,20,[85][86][87].Writing scaffolds, including prompts, sentence stems, writing frames, and graphic organizers, provide students with instructional assistance to move students toward a better understanding of the content [21,22,88,89].Peer review and sharing allow students to evaluate each other's work [90] and engage in processes similar to scientists by sharing completed work with others.

Listening
Acquiring language proficiency requires the essential receptive skill of listening, which is incorporated within the other language domains of speaking, reading, and writing.Language learning can be enriched through the engaging environment of science classrooms [41,91].The language of science comprises more than specialized vocabulary; it involves the development of thematic patterns through multiple modes of language [68].To support students in language development, teachers can scaffold their science language skills through modeling, cultivating science inquiry, and enhancing students' capacity to communicate about science.Through teacher talk and illustrating word usage, students' language proficiency can be elevated [92], leading to growth in vocabulary [93].
Since oral language serves as a fundamental building block for language and literacy development, a higher level of oral language proficiency correlates with increased vocabulary [94], leading to improved reading and writing [95,96].Students benefit from a vocabulary-rich science classroom, where their science vocabulary knowledge can be developed through listening to teachers' modeling of sophisticated words [93].Additionally, listening practices in science classrooms encompass students attentively listening to teachers and peers as they model the use of scientific language in complete sentences and engage in scientific discussions.Encouraging students to build a solid foundation in oral language skills, encompassing both speaking and listening, within the science classroom will help them become proficient readers and writers in science.

Purpose of the study and research question
The study aimed to investigate how seventh-grade teachers' use of LIS strategies changed after participating in eight monthly LIS virtual professional development sessions.The research question follows: In what ways did seventh-grade teachers' use of literacy-infused science (LIS) strategies change after their participation in eight monthly LIS virtual professional development sessions?

Research design
To address our research question, we initially used a pre-/post-survey to look at the magnitude of perceived changes among seventh-grade science teachers in their use of LIS as reflected in vocabulary, reading, writing, and speaking.Upon further reflection, it was necessary to clarify how the seventh-grade science teacher participants interpreted and applied the LIS strategies they had previously expressed in their pre-/post-survey responses.As the purpose of an explanatory sequential design is to use qualitative data to explain quantitative findings [97], we believed this research design methodology was the best fit to address our research question.For the quantitative phase of this mixed methods design, we analyzed variations among teacher responses to a 12-item literacy-infused science survey before and after a series of monthly VPD events.Then, we used end-of-year focus group interviews to interpret variations and differences among survey participants as the explanatory qualitative stage of the research design.

Intervention
Project Literacy Infused Science using Technology Opportunities (LISTO) provided participants with monthly VPD as part of a five-year randomized control trial (RCT) study to investigate the effectiveness of LIS interventions.VPDs were delivered through the video conferencing platform GoToTraining and Nearpod, a participant engagement tool.Integral parts of the LIS framework (e.g., explicit vocabulary instruction; strategic reading partners; graphic organizers; scaffolded scientific writing; and engaging questioning strategies) were organized into eight VPD sessions during the 2019-2020 academic year.Each VPD lasted approximately 60 min and used polls, open-ended questions, collaborative questions, and drawing activities to increase active teacher participation with the content.VPD's purpose was to assist science teachers in learning about LIS strategies and how to integrate them into their 1 3 science instruction.All the VPDs were video recorded and housed on a learning management system for participants to review or complete missed sessions.

Participants
As part of the RCT design, seventh-grade teachers were included in the study if their class rosters contained students who had previously participated in a literacy-infused science curriculum as fifth graders; for more detail about the original project design, see the Department of Education Grant #U411B16001.As students progressed through middle school, their teachers of record were invited to participate in VPD sessions focused on LIS pedagogical strategies.To be included in this study, participants needed to attend at least six out of eight VPD events and complete a LIS pre-/post-survey.Out of 24 participants, only 12 active participants met the inclusion criteria and were included in this data analysis (Table 1).The sample included two female teachers from non-rural school districts and ten female teachers from rural school districts.Most participants self-identified as mid-career teachers with 6-15 years of teaching experience.According to the Texas Education Agency 2019-2020 school report, all the participating schools were at least 50% EC, and the percentage of EB students ranged from 1.4% to 37%.

Pre-Post literacy-infused science survey
The research team developed a LIS survey to gather data quantitatively to ascertain participants' perceived level of literacy strategy use in their science instruction.Participants rated their level of implementation for 12 literacy strategies (Table 2) using a six-point Likert scale (0 = "not implementing, " 5 = "fully implementing").A literacy expert reviewed the survey to evaluate the content, cognitive, and usability standards to ensure the questions asked were about related information, easily understood, and could be responded to as intended.The initial LIS science survey was administered in November, and the post-survey in April after the final VPD session.The post-survey was administered before the end of the academic year due to the onset of the COVID-19 pandemic.This way, teacher responses were grounded in their typical lesson development and not swayed by their experiences adjusting instructional practice due to the pandemic.A Cronbach's alpha was used to measure the internal consistency of the LIS survey, resulting in a = 0.86, suggesting high internal consistency among the twelve items.

Focus group interview protocol
At the end of the 2019-2020 academic year, Project LISTO invited participating seventh-grade science teachers to take part in semi-structured focus-group interviews.Focus group interviews were intended to collect data that elicited the nuanced differences among teachers with a shared experience of participating in (a) monthly LIS VPD sessions and (b) enacting LIS strategies in their classroom instruction.A semi-structured focus group protocol was used to elicit comparable responses across focus groups while allowing the interviewer to probe further with follow-up questions based on the participants' initial responses.The coordinator team's elementary science education specialist evaluated previous teacher responses from the sixth-grade focus group interviews.Based on teacher responses, questions were modified for clarity, and additional questions were suggested focusing on implementation practices, future use of strategies, and impact on diverse student populations in the classroom.The questions were reviewed by an additional science education specialist and a bilingual education specialist to obtain face validity and ensure that they measured the VPD content, were easily understandable, and participants could respond as intended to get accurate and sufficient information.Focus group interviews were scheduled in 45 min sessions with an average group size of three participants.The purpose of this grouping design was to (a) minimize potential power dynamics which may inadvertently hinder participants' willingness to share openly and honestly, (b) minimize the potential of participants to avoid responding because a team member already shared a similar personal experience, and (c) reduce the potential of a co-located group of participants dominating the conversation, thereby isolating non-co-located teachers in the group.The focus group discussion protocol centered on the following topics: (a) the impact of VPD on teaching practice, (b) the implementation of LIS strategies, (c) the impact of LIS strategies on students, specifically diverse learners, and (d) future use of LIS strategies.
The research personnel who conducted the interviews consisted of an elementary science specialist, a middle grades science specialist, and a bilingual education specialist.All three interviewers have extensive experience with LIS and have conducted PD sessions and seminars on the topic.The focus group interviews were recorded using GoToMeeting, and transcripts were prepared and analyzed using TRINT, an audio transcription software.

Quantitative analysis
The data were analyzed using IBM SPSS Statistics (Version 26).We grouped the 12 questions into four categories: speaking, vocabulary, reading, and writing (Table 2).We calculated the difference between pre-/post-responses for each category and the complete LIS survey.Wilcoxon matched-pairs signed rank non-parametric test was used due to the data type, and it met the assumptions of non-normal distributed data.

Qualitative analysis
Four literacy-infused science categories were developed from the quantitative survey results and used as predetermined coding themes for analyzing the semi-structured focus group interviews (Table 3).Focus group transcripts were manually checked for accuracy by two research staff members.The transcripts were coded idea-by-idea and were extracted into a spreadsheet and sorted into four broad categories to mirror the categories from the pre-/post-literacy infused science survey: speaking, vocabulary, reading, and writing.Each code was further analyzed based on the level of detail provided and its relevance to the strategies as presented.For example, participant descriptions that included details that paired with content presented in VPD were coded as some evidence (SE), whereas participant descriptions of activities with details that did not align with VPD content were coded as modified (MOD).When a strategy was named, but insufficient details were provided to determine fidelity, it was coded as ambiguous (AMB).In the following example, a seventh-grade rural science teacher identified three different LIS strategies (vocabulary, post-reading activities, and sentence stems) with varying levels of detail provided.

Trustworthiness and credibility of the qualitative study
Specific to the qualitative component of the study, credibility was improved by triangulating data between two sources (LIS survey and focus group interviews), prolonged experience and relationship building with the participants (eight months), and continuous observations (virtual classroom observations).To increase the study's dependability, the researchers used an audit trail to describe how the data were collected, categories were derived, and coding decisions were made throughout the analysis [99].

Results
Participant responses to the literacy-infused science (LIS) survey and focus group interviews were analyzed from the perspective of the four LIS categories: speaking, vocabulary, reading, and writing.Study participants implemented more LIS strategies after participating in eight monthly LIS virtual professional development (VPD) sessions.We organized the results of the analyses by phase of the explanatory sequential mixed-methods study design.Interpretation of the results across the mixed method design was further examined in the following analysis section.

Quantitative data findings
Results of the pre-/post-LIS survey were organized into four LIS categories: speaking strategies, vocabulary strategies, reading strategies, and writing strategies.Means, standard deviations, and medians were calculated aggregately by LIS category based on the responses to each of the twelve items in the literacy-infused survey (Table 4).We used the Wilcoxon matched-pairs signed rank test to determine whether there was a difference between teachers' self-reported implementation of LIS strategies from before to after attending the LIS VPDs.The aggregate means of all pre-test (M = 33.25,SD = 9.89) items and post-test (M = 39.92,SD = 8.89) items indicate that participants implemented more literacy strategies after participating in VPDs.The analysis showed a significant difference between pre-and post-survey responses, z = − 2.59, p = 0.005, with a large effect size, r = 0.75 (Table 5).The results indicated that teachers self-reported an increase in the use of LIS strategies from pre-to post-survey. 1 3

Speaking strategies
Two items on the LIS Survey evaluated the participants' use of LIS strategies that supported science speaking skills.Speaking strategies included (a) enacting EQS and (b) promoting complete sentences.A Wilcoxon matched-pairs signed rank test was conducted to determine whether there was a significant difference in the use of speaking strategies between the pre-and post-survey responses.Results were not statistically significant, z = − 0.43, p = 0.67 (Table 5).

Vocabulary strategies
Two items on the LIS survey evaluated participants' use of LIS strategies that broadened science vocabulary-building skills.These vocabulary-building strategies included (a) explicit and scaffolded vocabulary instruction and (b) targeted vocabulary activities.A Wilcoxon matched-pairs signed rank test was conducted to determine whether there was a difference in the use of vocabulary strategies between the pre-and post-survey responses.The result indicated that teachers significantly increased their use of vocabulary strategies from pre-(Md = 5.5) to post-test (Md = 8.0), z = − 2.54, p = 0.005, with a large effect size, r = 0.73 (Table 5).

Reading strategies
Four items on the LIS survey evaluated participants' use of LIS strategies to support reading skills in science.These reading strategies included (a) strategically partnering students, (b) selecting and scaffolding appropriate science texts, and (c) implementing before, during, and after reading activities.We used a Wilcoxon matched-pairs signed rank test to identify whether a significant difference existed in teachers' use of reading strategies between the pre-and post-survey responses.
Our results demonstrated that teachers significantly increased their use of reading strategies from pre-(Md = 10.5) to post-test (Md = 14), z = − 2.83, p = 0.003, with a large effect size, r = 0.82 (Table 5).

Writing strategies
Four items on the Literacy-Infused Science Survey evaluated participants' inclusion of writing opportunities and scaffolds that supported scientific writing skills.We conducted a Wilcoxon matched-pairs signed rank test to determine whether there was a difference in the use of writing strategies between the pre-and post-survey responses.The result revealed that teachers significantly increased their use of writing strategies from the pre-test (Md = 11.5) to the post-test (Md = 12.5), z = − 2.15, p = 0.02, with a large effect size, r = 0.62 (Table 5).

Qualitative data findings
The following section presents an analysis of the semi-structured focus group interviews with the 12 teacher participants.Transcribed responses were coded idea-for-idea, and the codes were extracted into a spreadsheet and sorted into four broader categories: speaking, vocabulary, reading, and writing.Categorical ratings were assigned based on the level and content of the descriptions associated with each category.Of the 92 references to LIS strategies during the focus group interviews, just over half (52%) addressed reading-based strategies, writing strategies made up 42% of responses, and 21% discussed vocabulary strategies.Very few (3%) of the references addressed speaking LIS strategies.Each of the four broader categories were further described below.

Speaking strategies
During the focus group interviews, three references were made to speaking-specific LIS strategies consistent with the EQS presented in LIS VPDs (Table 6).Providing students with wait times before responding to posed questions and using randomization techniques to call on students were the primary speaking-specific LIS strategies associated with impacting science teaching and learning in the participant's classroom.
Something that I would like to try to be better at for next year is my questioning strategies.I will admit that I am the teacher that sometimes just calls on the first student who raises their hand because I'm ready to move on to the next topic.And I think that really not benefiting all of my students by doing that.So, it's going to take a real lifestyle change for me to do that one.

Vocabulary strategies
Participants referred to vocabulary-specific LIS strategies 19 times (21% of total LIS references; Table 7).Among these, 68% of the responses were described with some evidence consistent with the vocabulary-specific LIS strategies presented in VPDs.Three descriptions were ambiguous and lacked sufficient detail to align with the strategies presented in LIS VPDs.The remaining references included using gestures to support vocabulary use, expanding the targeted vocabulary list to include Spanish terms, and shifting from a traditional word wall to Spanish/English labels on classroom objects.Modeling vocabulary use and providing visual cues were two distinct vocabulary LIS strategies for helping EBs actively participate in vocabulary-centric experiences.
I mean, it was I was going over vocabulary, but, you know, I was just taking it an extra step further to help them break down, like how to pronounce it.You know, in the parts of the words and simple things that I just didn't do that I started to do.

Reading strategies
Participants referred to reading LIS strategies 48 times during the focus groups (Table 8).Four were general references to reading strategies without sufficient descriptions to associate them with a specific reading LIS strategy.Almost half (45%) of the remaining references included some evidence of the strategies presented in LIS VPDs.The remaining references were either ambiguous (25%) or described modifications (30%).Some strategies, like reading partners, were consistently referenced with sufficient detail to rate the teachers' understanding of the strategies and their likely implementation in the classroom.Among all the LIS strategies associated with reading skills, embedding read-alouds into the science curriculum was the only strategy teachers identified as uniquely beneficial to EBs.
There's a huge range of reading ability in my seventh graders.(…) So, I usually focus on group reading and using the strategies where we highlight and talk about the headings and how the material beneath each heading supports the reason for even having a heading.

Writing strategies
Twenty-two references were made about writing LIS strategies during the focus groups (Table 9).Sixty-eight percent included some evidence consistent with the methods presented in LIS VPDs.Pre-writing strategies (graphic organizer and sentence stems) were consistently described with sufficient detail to rate the teachers' understanding of the strategy and its likely implementation in their classrooms.Four references were ambiguous, including references to infusing writing with reading.Among all the LIS strategies associated with writing skills, including sentence stems in science lessons was the only strategy identified as uniquely beneficial to EBs.
I used a lot of graphic organizers.I found that that was very helpful with not only helping my regular students lay out their thoughts and improve literacy, but also it really helps my ELL's with their language abilities.

Discussion
Teachers should be mindful not only of science content but also of the role of language in the field of science [49] due to its complex vocabulary [46,48] and comprehension challenges experienced by EBs [15].The complex role of language in science prioritizes LIS strategies as an essential requirement for effective teaching practices [16,36].Providing PD opportunities focused on LIS strategies prepares teachers with the skills necessary to improve student outcomes in science and reading.This study aimed to investigate how seventh-grade teachers' perceived use of LIS strategies changed after their participation in eight monthly LIS virtual professional development sessions.Initial quantitative findings on the pre-/post-survey indicated that teachers perceived themselves to have a statistically significant increase in their use of LIS strategies; however, as we conducted end-of-year focus group interviews, patterns of use and variations in implementation emerged as valuable resources for interpreting the initial quantitative findings.

Summary of quantitative findings
Teachers in our study self-reported an increase in their use and intended use of literacy-infusion strategies after LIS VPD participation.We used the Wilcoxon matched-pairs signed rank test to compare differences in teachers' self-reported pre-/post-literacy-infusion implementation results.Findings from this analysis indicate an overall increase in the selfreported use of LIS strategies.This increase mirrors the findings of other self-reported data among interventions delivered through professional development activities [100][101][102].Further investigation of these findings revealed that vocabulary, reading, and writing strategies were statistically significant among teachers' pre-to post-survey responses.Speaking strategies were not statistically significant; however, this may have had to do with the limited time between its introduction through VPD and the time remaining before the close of the academic year.Other strategies were introduced earlier, and teachers had more opportunities to implement them in their classes.Results are consistent with the findings of Yoon et al. [103] associating implementation fidelity and its relationship to time spent presenting new strategies and paired opportunities to implement.Previous researchers [104][105][106] have found positive effects on teacher pedagogy when PD is content-focused and occurs over an extended period.These results add to the field by confirming the associated benefits of PD when delivered through synchronous virtual tools.Additionally, findings from this study extend the associated benefits of linking PD with implementation opportunities among middle-grade science teachers [25,103] to include PD delivered online (VPD).Limitations of VPD include inconsistent teacher attendance, inconsistencies in active participation as reflected in responding to all polls, quizzes, etc., and general technology issues (logging in, staying logged in, and actively engaging simultaneously in two online platforms).Data impacted by these limitations were excluded through our sampling procedures.

Summary of qualitative findings
We used an idea-by-idea analysis of recorded and transcribed participant responses from focus group interviews to elicit a richer, more descriptive account of which specific LIS strategies teachers found most impactful overall.Reading strategies represented over half (52%) of LIS references among the responses included in the focus group interview data.These references to reading LIS strategies were predominantly associated with setting up reading partners (27%) and utilizing pre-reading activities such as previewing text features (23%) and selecting scaffolded texts (10%).While the use of reading partners was typically described in ways consistent with the strategies presented in LIS VPDs, other strategies, like the descriptions of pre-reading and post-reading activities, were more ambiguous.The discipline-specific pedagogical knowledge associated with implementing a strategy such as reading partners requires less context-dependent training.Once students' reading levels are used to match partners and students learn their roles, this strategy can be implemented across various science texts with little implementation from the teacher.Organizing reading partners is also a high return on investment strategy, as it can be used with various text-based reading activities in science.In contrast, selecting text features and non-academic words in a pre-or post-reading strategy requires a stronger self-efficacy in reading as an out-of-discipline content area [18,37,102].Vocabulary and writing-based LIS strategies split the remaining references, with 24% and 21%, respectively.The most common references to vocabulary LIS strategies were the integration of online vocabulary games as well as supporting students by explicitly teaching target vocabulary, including decoding meaning and modeling pronunciation.Berne & Blachowicz [107] found that teachers reported focusing on word relationships, read-alouds, songs, and games to promote vocabulary instruction.They indicated that vocabulary instruction was problematic for teachers because they "did not know where to begin to form an instructional emphasis on word learning" [107].This may indicate that decontextualized vocabulary activities that draw on competitive games are more frequently infused into science instruction because the requirement of science teachers to stretch their out-of-discipline knowledge is minimal.The writing strategy references emphasized using anchor charts and other graphic organizers as a pre-writing tool.Few references were made to EQS, such as randomly selecting students to share and providing student wait time for verbal responses-both associated with the speaking LIS strategies (3%) presented in LIS VPDs.

Integration of findings
Findings from the focus group interviews mirrored results among the quantitative survey responses-particularly regarding the prevalence of reading, writing, and vocabulary LIS references and described benefits to the teachers and students.As an explanatory sequential mixed-methods design, we looked at the presence, detail, and description of LIS strategy implementation to better interpret the statistically significant differences represented in the quantitate analyses of the LIS survey responses.Based on the improvements from the pretest to the post-test in tandem with the focus group interviews, we conclude that LIS VPDs improved the participating middle school science teachers' pedagogical knowledge and practice in implementing reading, writing, and vocabulary instructional strategies.The speaking-related LIS strategies presented in LIS VPD occurred in the spring semester; altered instruction due to COVID-19 may have hindered post-test gains among the seventh-grade science teachers.

Conclusions and implications
Although teachers who participated in this study reported a change in their teaching practices and use of LIS strategies, comments from the focus group interviews suggest the time provided to teachers in VPD may have been insufficient for teachers to develop a deep understanding of what constitutes a LIS strategy or how to implement them effectively in the classroom.These findings may emphasize the need not only to increase the frequency of VPD but also to attach virtual coaching opportunities to ensure implementation fidelity.For example, Cantrell and Hughes [100] found that after a week-long summer institute, extensive monthly coaching increased teachers' implementation of literacy into the content curriculum.With targeted feedback from VPD facilitators, teachers may be better able to integrate LIS strategies into their science lessons, providing more equitable interventions for all students.Future researchers should investigate the impact of LIS VPD on implementation fidelity by analyzing teacher observations during and after LIS VPD.Participating teachers in Project LISTO reported utilizing more literacy-infused science strategies after monthly VPD sessions.Analysis of the focus group interviews indicated that teachers often modified LIS strategies.Regardless of teacher modification of strategies and the level of implementation, teachers reported perceived benefits of implementing LIS strategies with their students.When middle school science teachers are taught and made aware of LIS strategies, their usage in the classroom-even in a modified form-increases.We recommend training middle school teachers who may have limited training in English/language arts pedagogy to develop science lessons with a focus on LIS to provide equitable interventions for all students, particularly EBs and ECs.

Fig. 1
Fig. 1 Four literacy domains included in literacy-infused science

Table 2
Literacy-infused science survey items Survey Question Speaking strategies In reflecting on your science instruction, slide the scale to indicate where you feel you are in implementing the following literacy strategies during your science instruction: Engaging questioning strategies (think time, all students respond -think-pair-share, choral response, visual cues, dry-erase boards, randomly select students to share out with the class, provide specific content feedback that reinforces science content) Encourage students to respond in complete sentences Vocabulary strategies In reflecting on your science instruction, slide the scale to indicate where you feel you are in implementing the following literacy strategies during your science instruction: Explicit and scaffolded vocabulary instruction (syllable breakdown, part of speech, authentic image, student-friendly definition, sentence stem/discussion prompt) Vocabulary activities (T-chart, matching, word web, diagram, give an example, synonyms & antonyms) Reading strategies In reflecting on your science instruction, slide the scale to indicate where you feel you are in implementing the following literacy strategies during your science instruction: Scaffolded reading passages (selected based on readability, assigned reading directly aligned to TEKS, selection includes expository text features such as headings, subheadings, boldface terms, captions, images, diagrams) Before reading strategies (preview vocabulary, model/practice pronunciation of tricky words, preview target questions, preview graphic organizer, preview expository text features) During reading strategies (strategic partner reading, reinforce text features, partners discuss comprehension) After reading strategies (check for understanding, guide students to provide text evidence, identify expository text structure-description, sequence, compare/contrast, cause/effect, problem/solution, related journal entry) Writing strategiesIn reflecting on your science instruction, slide the scale to indicate where you feel you are in implementing the following literacy strategies during your science instruction: Anchor chart (graphic co-created throughout the unit to reflect learning) Writing opportunities (journal entry, field notes, data tables, lab reports, claim/evidence/reasoning, perspective-based writing, essay, multimedia presentation) Writing scaffolds (brainstorming, graphic organizer, shared-writing, sentence stems, rubric) Post-writing activities (peer review, class presentation, gallery-walk, school audience, class newsletter, sharing out with campus or community)

Table 3
Qualitative codes for literacy-infused science strategies

Table 4
Descriptive statistics of literacy-infused science survey by 4 categories (n = 12)

Table 5
Results of Wilcoxon Matched pairs signed rank test for the literacy-infused science survey pretest-posttest scores by four categories (n = 12) a Based on negative ranks b p <0.05 c p < 0.01

Table 8
Literacy-infused science strategies reading implementation fidelity quality results AR refers to accelerated reader while STAAR refers to the State of Texas Assessments of Academic Readiness Reading Strategies

Table 9
Literacy-infused science strategies writing implementation fidelity quality resultsWriting strategies