Applying an Allportian Trait Perspective to Sense of Purpose

Sense of purpose captures the extent to which one feels that they have personally meaningful goals and directions guiding them through life. While this construct has illustrated its ability to robustly predict desirable outcomes—ranging from happiness to mortality—the nature of this construct remains unclear. I begin by describing different definitions and measures from the purpose literature. From there, I review the debates suggesting that it should be classified as a component of identity development, a facet of well-being, or even a virtue. In the current paper, I argue that sense of purpose could be best served when qualified as a trait, building from the eight components of defining a trait from Allport’s (1931) paper: “What is a trait of personality?”. Using this classic piece as a framework, I integrate empirical and theoretical work on purpose and personality to dive into whether sense of purpose is a trait. I conclude by discussing the challenges and implications of bolstering sense of purpose if it is best classified as a trait.


Defining Sense of Purpose
The lack of clarity around the nature of this construct may be, in part, due to the various definitions and assessments associated with it. Table 1 includes a list of foundational purpose papers, their definitions of purpose and, when applicable and available, their measures. Clearly, the usage of terms to describe sense of purpose is convoluted: in certain cases, the same term is used to describe different conceptualizations of purpose. For example, purpose in life in Ryff's (1989) and Scheier et al.'s (2006) representation of purpose represents a construct experienced on a spectrum, with higher scorers agreeing that items such as "I have a sense of direction and purpose in my life" and "To me, the things I do are worthwhile" describe them well. However, McKnight and Kashdan (2009) use this same term to describe "a central, self-organizing life aim that organizes and stimulates goals, manages behaviors, and provides a sense of meaning" (p. 242), rather than how purposeful one may feel. Damon, Menon, and Bronk (2003) build from this idea of an individual's overarching goal for life with the additional criterion of that goal needing to help others to be identified as a purpose.
In other instances, different measures are used assess the same construct. For example, Hill et al.'s (2016) conceptualization of purpose aligns with that of Ryff's (1989) and Scheier et al.'s (2006), insofar that their measure was developed to assess one's feelings of purposefulness rather than the presence or orientation of an individual's specific broader life aim. As with efforts made by Scheier et al. (2006) in the development of the Life Engagement Test from the Purpose in Life subscale (Ryff, 1989), Hill and colleagues (2006) sought to develop a measure that took out the role of reflecting over extensive periods of time in determining one's feelings of purposefulness. For example, in Ryff's (1989) Purpose in Life subscale, items such as, "I sometimes feel as if I've done all there is to do in life," requires a level of time sensitivity that Scheier et al. (2006) and  worked to remove. Thus, while each of these measures can be connected to how purposeful an individual feels, and the extent to which they are following a direction through life, these more recent measures aim to capture feelings of purposefulness in the moment rather than across the entirety of one's lifespan. In particular, these measures do so by focusing on the perceptions of one's activities being perceived to be purposeful and connecting with their broader goals for life (e.g., "To me the things I do are worthwhile," Scheier et al., 2006). Finally, across each of these measures and as a primary focus of the Life Engagement Test, sense of purpose is also represented by perceiving one's activities as being personally meaningful (e.g., Ryff's (1989) item: "My daily activities seem trivial and unimportant to me; Scheier et al.'s (2006) item: "I value my activities a lot").
Moving beyond what purpose entails to what different purpose terms represent, with the Brief Purpose Measure  we begin to see a transition away from the term purpose in life being used to reflect how purposeful one feels; instead, the authors interchangeably used the more classical terms of purpose in life with sense of purpose and sense of purpose in life . This article helped ignite the transition to purpose in life capturing the articulated life aim that likely bolsters one's sense of purpose, rather than Note. * represents an item that must be reverse scored when computing a sense of purpose composite one's sense of purpose levels themselves. In line with these insinuated distinctions and the summation of past work, Pfund (2020) stated that purpose can be divided into two interrelated but distinct constructs: sense of purpose, the extent to which one feels that they have personally meaningful goals and directions guiding them through life, and purpose in life, an individual's specific overarching goal and direction. The current work will use this same dual-faceted conceptualization of purpose; in particular, I will be focusing on how sense of purpose may be best understood as a trait, but mentioning purpose in life as is relevant to the categorization and comprehension of this construct. Finally, I will use the term purpose when referring to the broader literature across constructs or when referring to research that do not as cleanly distinguish sense of purpose and purpose in life.

Classifying Sense of Purpose
Though research on purpose has increased over the past several decades, the classification of this construct has drastically varied. Some consider sense of purpose as a component of well-being (Willroth, 2022), as in a necessary facet of what it means to be psychologically well. More specifically, sense of purpose has been deemed a domain of psychological wellbeing (Ryff, 1989;Ryff, 1995;Ryff, 2014), which emphasizes the more eudaimonic (i.e., feeling engaged with one's life) rather than hedonic (i.e., feeling content with one's life) form of the good life (Ryff & Boylan, 2016). Meanwhile, others assert that purpose in life is part of identity development (Bronk, Hill, et al., 2009;Hill & Burrow, 2012;Sumner et al., 2015), given that the process of figuring out one's goals for life is necessarily informed by and also informs who they are. Finally, some take a moralistic perspective, claiming that living purposefully is a virtue or character strength (Han, 2015;Ryff & Kim, 2020). In fact, some researchers suggest that if one's purpose in life is not "beyond the self," then they cannot be classified as having a purpose at all (Damon et al., 2003). However, this definition is fairly contentious, as some state that it should not be in the hands of the researchers to determine whether individuals' purposes are worthy , and others have noted that the vast literature focusing on the benefits of purpose has used sense of purpose measures agnostic to an individual's specific purpose orientation (Hill & Pfund, 2022). The classification of purpose in psychological sciences varies and is in part based on whether one is focusing on sense of purpose versus purpose in life. More recently, work has begun to explore whether sense of purpose is more accurately identified as a trait (Pfund, 2020), or a construct that illustrates consistencies in thoughts, feelings, and behaviors between individuals across similar situations (Roberts, 2009). Establishing what sense of purpose can be categorized as is a necessary step in understanding how to help individuals develop and harness it. Additionally, determining an accurate classification of this construct provides guidance on both intervention ease and opportunities. Personality traits are often considered challenging to change, relative to other more malleable constructs like affect, which have been intervened upon using psychotherapeutic, experimental, and humanistic efforts (Boumparis, Karyotaki, et al., 2016;Heekerens & Eid, et al., 2021;Schutte & Malouff, 2019;Taylor, Lyubomirsky, & Stein, 2017). However, there is initial evidence that these dispositional characteristics can potentially be manipulated when utilizing intensive interventions (e.g., Hudson & Fraley, 2015;Hudson, Fraley, et al., 2021;Stieger, Flückiger, et al., 2021). Thus, to determine whether sense of purpose is a trait will be crucial in understanding if, when, and how we can change it, the challenges that will arise if we attempt to do so, and the methods that may be most effective in assuring that more individuals can benefit from the desirable outcomes sense of purpose predicts.
3 The Trait-like Nature of Sense of Purpose Using Allport's (1931) foundational paper "What is a trait of personality?", I will discuss the eight components he set forth as necessary criteria to warrant the classification of this term, while also integrating more recent literature that evaluates these initial claims. Traits are commonly understood as consistency in thoughts, feelings, and behaviors across similar situations Roberts, 2009). Thus, to consider sense of purpose as a trait, one must think through whether and how sense of purpose may be composed of thoughts, feelings, and behaviors. On the cognitive front, sense of purpose has illustrated cognitive patterns (Lewis, 2020), insofar that purposeful individuals are typically more likely to recognize pathways necessary to overcoming obstacles and thinking of themselves as more capable to doing so (Bronk et al., 2009). Moreover, purposeful individuals are more likely to engage in coping strategies that rely on thinking of the bigger picture and finding the silver lining in challenging and anxiety-provoking situations (Author Citation), rather than ruminating or avoiding their problems (Lohani et al., 2022).
Sense of purpose has also been connected to affective tendencies in a few primary ways. First, people with a higher sense of purpose generally experience more positive emotions and fewer negative emotions, both in general and in daily life (Hill, Sin, et al., 2018;Pfund, Ratner, et al., 2021). Moreover, purposeful individuals experience less of an increase in negative affect following a stressor (Hill, Sin, et al., 2018) and less of an increase in positive affect following a positive event (Hill, Sin, et al., 2022), suggesting that sense of purpose may help promote less reactivity in daily emotions. This lower affective reactivity may also be due to how purposeful people rely on typically more effective and adaptive coping and emotion regulation strategies (Author Citation;Lohani et al., 2022).
Finally, when thinking through the behavioral aspects of sense of purpose, past work on purpose in life has noted that one's purpose guides their daily behaviors (McKnight & Kashdan, 2009). However, unlike the cognitive and affective tendencies sense of purpose promotes, the behavioral components of purpose may be more idiosyncratic in nature. One quirk when thinking through sense of purpose as a trait may stem from the unique behavioral tendencies that likely differ across individuals depending on what it is that makes them feel purposeful. The Purpose as a Trait, Habit, and State (PATHS) Model has explored how one's purpose in life likely shapes one's daily activities (Hill, Pfund, & Allemand, 2023). Thus, how purpose promotes behavior likely differs depending on what one's specific life aims may be. Put differently, a given individual's purpose-produced behaviors could be consistent over time for them but different from another purposeful person's behaviors.
While this more concise definition of a trait may suggest sense of purpose could be a trait, the utilization of Allport's (1931) initial trait criteria in understanding the nature of sense of purpose provides a more conservative and in-depth interpretation of the construct. Thus, the following section will breakdown the nature of purpose through these eight separate trait principles. In order, these sections will consider if it (1) is a construct without implications, (2) a habit rather than a disposition, (3) solely a correlate of related variables instead of its own construct, (4) empirically established, (5) independent enough from other variables, (6) not a moral characteristic, (7) fairly consistent within an individual, while (8) still recognizing that within-person variability can exist. In each of these sections, I will discuss both how we know that it fits the relevant criterion as well as what may be missing to draw these conclusions. This paper will then conclude with a reflection on the implications of trait classification for sense of purpose. Allport (1931) suggests that a trait must have "more than a nominal existence" (p. 368), meaning that a disposition is not simply a framework that describes a person, but also is responsible for a collection of habits that align with the trait itself. Over the several decades in which the study of sense of purpose has prevailed, this construct's definition has held a few core commonalities, as well as some differentiated nuances (Hill, Burrow, et al., 2010). However, across the most common conceptualizations of purpose (Damon et al., 2003;Kosine, Steger, & Duncan, 2008;McKnight & Kashdan, 2009;Ryff, 1989), one theme that constantly emerges regarding sense of purpose is being rooted in feeling that one has overarching aims for life (Hill, Burrow, et al., 2010). Those life aims provide a direction and a framework for individuals to set smaller and more specific goals in both the short-and long-term (McKnight & Kashdan, 2009).

Sense of Purpose is More than a Name
Furthermore, purpose has been described as "a higher-order cognitive process which reciprocally stimulates goal selection and long-term goal maintenance," (Lewis, 2020). In other words, people with a higher sense of purpose will be more likely to focus on long-term goal attainment by adjusting their actions and behaviors in the short-term to align with those future-oriented life aims that bolster their purposefulness. In both conceptualizations, purpose is described as a broader construct that, in turn, influences smaller happenings within an individual along the way. It is no surprise then that individuals with a higher sense of purpose find their daily activities more personally meaningful, and greater aligned with their directions for life (Scheier et al., 2006). Allport's (1931) suggestion that our tendencies are more than simply generalized habits, and are rooted in broader, dispositional constructs distinguished as traits, is reflected in sense of purpose. Allport (1931) also highlighted that "a trait is more generalized than a habit" (p. 368), and that "there may be said to be major, widely extensified traits, and minor, less generalized traits in a given personality," (p. 369). Thus, sense of purpose does not need to supersede the existence of the Big Five personality traits to prove that it is a trait; rather, this construct must illustrate that it can explain a collection of habitual tendencies within or between individuals. The focus on narrower traits, like sense of purpose, responds to both new and old calls within personality science. Goldberg (1993) noted decades ago that "It should be clear that proponents of the five-factor model have never intend to reduce the rich tapestry of personality to a mere five traits… Rather, they seek to provide a scientifically compelling framework in which to organize the myriad individual differences that characterize humankind," (p. 27). And, while the Big Five does provide a common system and language for personality scientists to use that plays an important role in the advancement and progress of trait theory, more recent work has reiterated the historical calls of Goldberg (1993) by illustrating the necessity of specificity when researching these traits.

Sense of Purpose is More than a Habit
In particular, there have been calls to go beyond the "Big Few" in personality psychology and focus on the lower-order individual differences in trait hierarchies ranging from domains and facets to the newly emerging nuances Condon, 2018;Costa & McCrae, 1995;Mõttus et al., 2020;Paunonen & Ashton, 2001). Narrowing in on these lower-order individual differences better meets the goal of personality science to predict, explain, and describe (Mõttus, Wood, et al., 2020). In fact, research focusing on nuances, which can be understood as "the lowest level at which patterns of responses to items continue to have reliable specific variance," (Condon et al., 2020, p. 925), typically enabling better predictions than broader traits (Hall & Metz, 2020). Thus, if sense of purpose can show itself to be more than an individual habit, it will meet the calls of personality researchers across the decades to investigate more than the broadest level of individual differences.
Allemand and Flückiger (2017) highlight that a trait is a broader version of a collection of habits, and habits are often composed of momentary states. Building from this same framework, the PATHS model has since clarified how purpose can function as both a habit and a trait (Hill et al., 2023). Specifically, Hill and colleagues suggest that one's overarching purpose in life likely guides one's automated (i.e., habitual) thoughts, feelings, and behaviors as they in line with one's purpose in life. Relatedly, purpose is theorized to guide both the creation of minor goals and the behaviors that coincide with them (McKnight & Kashdan, 2009). Furthermore, with a main component of sense of purpose being personally meaningful activity engagement (Scheier et al., 2006), purposeful people's daily habits are likely either perceived to be more meaningful or that purposeful people are better at engaging in more meaningful activities than their lower sense of purpose counterparts. However, it may, in fact, be both: People with a higher sense of purpose report more positive daily events on average (Hill, Sin, et al., 2020); meanwhile, though sense of purpose is not associated with number of daily negative events, more purposeful people experience less of an increase in negative affect when experiencing a stressful event (Hill, Sin, et al., 2018). With habits being understood as an automatic tendency (Hull, 1930), Hill et al.'s (2023) more complex descriptions of purpose as a trait and habit may be more accurate. Sense of purpose may be connected to automatic, habitual tendencies in individuals' interpretation of daily life, as well as the more active and intentional way that individual's choose to live their daily lives.

Sense of Purpose is More than a Correlate
Another inherent component of traits in Allport's (1931) definition is that they are, "dynamic, or at least determinative," (p. 369). This condition is easily met with sense of purpose given that research abounds across a variety of domains highlighting that sense of purpose is not simply a correlate of outcomes, but a predictor and promoter of outcomes. As already mentioned, sense of purpose is a cognitive framework that directs short-and long-term goals, behaviors, and resource allocation (Lewis, 2020;McKnight & Kashdan, 2009). While the opening of this paper illustrated the far reach of sense of purpose regarding the critical outcomes it promotes, the current section takes a deep dive into one area of research to illustrate what may be interpreted as the determinative nature of sense of purpose.
When focusing specifically on the longitudinal associations between purpose and physical health, people who have a lower sense of purpose are more at risk for cardiovascular events (Cohen, Bavishi, & Raozanski, 2016;Kim, Sun, et al., 2013), stroke (Kim, Sun, Park, & Peterson, 2013b), physical disability (Mota, Tsai, et al., 2016), and experiencing poorer subjective health overall (Windsor et al., 2015). These results align with potential mechanistic findings about purposeful people enacting better health behaviors like greater vegetable intake, more frequent flossing, and greater moderate and vigorous physical activity Hooker & Masters, 2016;Pfund, DeLongis, et al., 2022); moreover, people with a higher sense of purpose report greater utilization of preventative health care services (Kim, Strecher, & Ryff, 2014). It is no surprise then that older adults who report a higher sense of purpose also report lower mortality rates (Boyle, Barnes et al., 2009;Hill & Turiano, 2014;Windsor et al., 2015). These findings hold when controlling for a variety of outcomes, ranging from depression (Boyle et al., 2009) to the Big Five personality traits , which will be discussed further in the next section. Pursuing one's purpose in life necessitates a healthful future in which one has the time and the ability to pursue one's life aims. The current discussion is one of many which exemplifies that sense of purpose is more than a simple correlate of crucial outcomes and shows the mechanistic pathways between sense of purpose and these desirable outcomes.

Sense of Purpose is Empirically and Statistically Established
In the next section of his paper, Allport purports that "the existence of a trait may be established empirically or statistically," (p. 370). There are a few ways in which sense of purpose meets this call through both its statistical distinction and its test-retest reliability. Regarding the first point, in the development of Purpose in Life subscale (Ryff, 1989;Ryff & Keyes, 1995), the authors assured that it was statistically unique from related constructs. The authors used factor analyses across several samples to find that sense of purpose was distinct from five other factors that comprised psychological well-being (Ryff, 1989;Ryff & Keyes, 1995). In fact, these findings hold up when considering the convergent validity using partner reports (Schmutte & Ryff, 1997). Given the nature of what that particular scale was assessing, future sense of purpose measures tried to address the possibility that this measure was confounded with well-being.
The Life Engagement Test was developed with eight separate samples to focus on feeling that one has valued goals and meaningful activities "because they provide a purpose for living," (Scheier et al., 2006, p. 291). This scale addressed concerns about the former by intentionally disentangling the developed items from associated constructs like life satisfaction and contentment, illustrating convergent validity with related variables such as self-esteem, optimism, self-mastery while maintaining correlations of a size to illustrate the constructs were distinct. Research has also considered both the test-retest reliability the Life Engagement Test assessed the test-retest reliability in four of its eight original samples by following up the participants four months after the original assessment (Scheier et al., 2006). The associations of these follow-ups ranged from 0.61 to 0.76, suggesting an appropriate amount of stability of this measure. The development of these commonly used measures support both the statistical and empirical establishment of sense of purpose.

Sense of Purpose is Fairly Independent
Allport also aptly notes that, "traits are only relatively independent of each other," (p. 370). Some have suggested that sense of purpose, given its goal-directed nature, may fall under the categories of conscientiousness (Goldberg, 1999), which is often defined as, "a spectrum of constructs that describe individual differences in the propensity to be self-controlled, responsible to others, hardworking, orderly, and rule-abiding," (Roberts, Lejuez, et al., 2014). Others have purported that high sense of purpose is simply the combination of high conscientiousness and high extraversion (Hofstee et al., 1992), the latter of which can be understood as high sociability, activity-orientation, and assertiveness (John, Nauman, & Soto, 2008). However, through large meta-analytic projects as well as projects illustrating its incremental validity alongside correlated constructs, sense of purpose has revealed itself to be a "relatively independent" construct.
First, meta-analytic work has unveiled that sense of purpose is associated with various personality facets and traits, though not to an extent that it appears to be capturing the same dispositional tendency within a person. One study looked at the associations between Ryff's (1989) Purpose in Life subscale with traits from both the Big Five and HEXACO (Anglim, Horwood, et al., 2020). In both personality trait frameworks, the strongest associations with purpose were displayed with conscientiousness. For the 15 studies that used the NEO Big Five measure (n = 5,699), the association between sense of purpose and conscientiousness was strongest, at 0.50 (95% CI [0.44, 0.55]), followed by the negative association between sense of purpose and neuroticism (r = − .45, 95% CI [-0.51, − 0.38]). People who are high on conscientiousness are generally orderly, industrious, and self-disciplined (John et al., 2008). While sense of purpose may not necessarily be connected to being orderly, the industriousness facet of conscientiousness likely taps into what Ryff (1989) sought to capture in sense of purpose items such as, "I enjoy making plans for the future and working to make them a reality." Moreover, with a major aspect of neuroticism being negative affectivity (Wilt & Revelle, 2015), and work connecting sense of purpose to fewer negative emotions and lower stress reactivity (Hill, Sin, et al., 2018;Pfund, Ratner, et al., 2021), the negative association between sense of purpose and neuroticism can likely be explained through these contrary affective dispositions.
Meanwhile, for the five studies that used HEXACO (n = 2,033), the association between purpose and conscientiousness was strongest, at 0.47 (95% CI [0.43, 0.50]), followed by that with extraversion (0.41, 95% CI [0.33, 0.49]). In both cases, sense of purpose showed a notable positive correlation with conscientiousness, but not of a magnitude that causes concern for these constructs overlapping; the positive associations with conscientiousness and extraversion and the negative association with neuroticism align with correlations found in less represented samples as well (Meléndez et al., 2019). Other research has explored the association between sense of purpose with specific personality trait domains. In these studies, sense of purpose was most strongly associated with the industriousness aspect of conscientiousness-though not the organization aspect-and the enthusiasm aspect-but not the assertive one-of extraversion (Sun et al., 2018). According to Allport (1931), the associations between traits is to be expected, and, as such, the existence of associations does not undermine sense of purpose as a unique construct. In fact, these associations help us better understand the nuanced sense of purpose-Big Five connection, insofar that purposeful people seem to be hardworking, enthusiastic, and generally more emotionally stable, but not necessarily more assertive or organized.
One limitation with this approach is that it only considers the zero-order correlation between sense of purpose and these traits and, as such, does not account for whether there is unique variance in sense of purpose when accounting for all these traits. A method to address this limitation is to consider whether sense of purpose predicts outcomes above and beyond correlated variables, the support for which is vast. When accounting for the Big Five specifically, sense of purpose predicts better subjective health outcomes and health behaviors (Hill, Edmonds, et al., 2016;Hill, Edmonds, & Hampson, 2019) greater initial and prospective income and net worth (Hill, Turiano, et al., 2016), as well as romantic relationship satisfaction and commitment (Pfund, Brazeau, et al., 2020). However, the Big Five personality traits are not the only constructs with which researchers fear for purpose's overlap.
The covariance of Ryff's (1989) sense of purpose measure and different aspects of wellbeing has been one of particular concern (Scheier et al., 2006). In this regard, some work has considered whether Ryff's (1989) sense of purpose measure predicts outcomes when controlling for depression. One study found that sense of purpose predicted risk for mortality when accounting for depression, as well as neuroticism and disability (Boyle et al., 2009). These findings are in part explained by research on sense of purpose and health behaviors. For example, more recent work has found that sense of purpose predicted walking speed in older adults while accounting for depressive symptoms, baseline health factors, and health behaviors (Kim, Kawachi, et al., 2017), and it predicted physical inactivity, sleep problems, and unhealthy BMI risks when accounting for health status and depression (Kim, Shiba, et al., 2020). Finally, when considering affective well-being and the Big Five personality traits, research has found that sense of purpose predicts romantic relationship quality across the lifespan (Pfund, Brazeau, et al., 2020) as well as better relationship satisfaction with parents and university friends in college students (Pfund et al., 2022). Thus, it is not simply that purposeful people feel more positively. In line with suggestions that purposeful people are better at organizing their day-to-day activities (McKnight & Kashdan), having a higher sense of purpose may connect to prioritizing the people in their lives, helping support better relationship outcomes. Across depressive symptoms, personality traits, and affective well-being, sense of purpose displays incremental validity, supporting the "relative independence" for which Allport (1931) calls in establishing a trait.

Sense of Purpose is Not a Virtue
The trait criterion with which I anticipate the greatest conflict regarding sense of purpose is that "a trait of personality, psychologically considered, is not the same as moral quality," (Allport, 1931, p. 371). However, the extent to which one would classify sense of purpose as a moral characteristic is dependent upon the definition of purpose that they follow. Damon and colleagues (2003) defined purpose as, "a stable and generalized intention to accomplish something that is at once meaningful to the self and of consequence to the world beyond the self," (p. 121). This focus on prosociality has been emphasized as one of the core commonalities of different purpose definitions (Hill, Burrow, et al., 2010), which likely explains why some have begun describing purpose as a virtual or character strength (Han, 2015;Ryff & Kim, 2020). However, some have clarified the original prosocially-oriented language of Damon and colleagues' (2003) definition of purpose by stating that the "action in the broader world can be prosocial, antisocial, or neutral in nature," (Bronk, 2011, p. 33). While this statement takes the morality out of the previous definition, it is also important to note that the other commonly used measures of sense of purpose make no mention of purpose helping others or needing to affect others at all Ryff, 1989;Scheier et al., 2006).
In fact, this purpose definition as one without a morally valenced view actually aligns with Allport and Odbert's (1936) original categorization of purposefulness into the extensive group of personal traits which were "generalized and personalized determining tendencies-consistent and stable model of an individual's adjustment to [their] environment" (p. 26) and were also described as "more neutral and less censorial" relative to some of the other word groupings. Thus, when considering more recent interpretation of Damon et al.'s (2003) definition of purpose, the sense of purpose measures being used in the current paper Ryff, 1989;Scheier et al., 2006), or even Allport and Odbert's (1936) expansive list of characteristic groupings, sense of purpose is likely not a moral quality. The measures of interest in the current paper do not assess the quality or nature of the activities and direction of individuals, and, as such, are not attached to a societal norm of morality or virtue.
Even if it were the case that the current work's definition of sense of purpose could be classified as a moral quality, Allport (1931) also acknowledged that there are likely instances where a construct "with social significance, may likewise represent true traits of personality," (p. 371). Allport and Odbert (1936) later expand on this reasoning, explaining that the consistency of thoughts, feelings, and behaviors of characteristics tied to social judgements may be followed due to people's desire to meet social norms rather than the characteristics themselves being trait-like. Furthermore, Allport (1927) expressed concerns that these moral evaluations likely differ across locations and time. With some definitions of purpose requiring the extra criterion of being beyond-the-self or worthwhile as defined by the researchers (Bronk & Damon, 2021), these critiques align with those put forth by other purpose researchers that to evaluate worthiness requires a level of subjectivity that also ignores the broader and various social contexts in which individuals exist . Thus, calls have been reiterated to remove the researcher's judgement and evaluation of an individual's own purpose from the process of declaring them as purposeful, and simply assess whether they have a higher or lower sense of purpose (Hill & Pfund, 2022).
Finally, though not the expressed concern of Allport (1931), some might feel skeptical of the inclusion of sense of purpose as a trait given its connection to well-being. Earlier on in its creation as a construct, it was viewed as one of six indicators of psychological wellbeing (Ryff, 1989;Ryff & Keyes, 1995). There are two primary arguments to address here. First, purpose and well-being, though associated, can exist without each other (Baumeister & Vohs, 2013); thus, someone can be high on trait sense of purpose while still having lower well-being or vice versa. Second, ample research has illuminated that different aspects of well-being can be trait-like. For example, positive and negative affect, key components of subjective well-being, are often considered to be fairly dispositional in nature (Tellegan, 1985;Watson & Clark, 1999), and some indicators of psychological well-being show relative lifespan stability (Mann, Deyoung, & Krueger, 2021). In the multifaceted realm of wellbeing research, both subjective well-being and self-esteem are constructs often described as traits (Luhmann et al., 2014;Ormel, VonKorff, Jeronimus, & Riese, 2017;Orth & Robins, 2014). Additionally, broad frameworks of personality psychology, such as the Neo-Socio-analytic Framework of Personality, include the Big Five personality traits plus positive and negative affect as traits (Roberts & Nickel, 2017). Thus, even if sense of purpose is potentially a component of well-being, that should not, in turn, disqualify it as a trait. Between this point and the separation from the value-laden terminology by which Allport (1931) was concerned, sense of purpose continues to fit the necessary criteria to be identified as a trait.

Sense of Purpose is Consistent Enough
Allport's penultimate criterion for what he considers qualities of a personality trait focuses more on what a trait does not have to have rather than what it does: "acts, and even habits, that are inconsistent with a trait are not proof of the non-existence of the trait," (p. 371). In other words, an individual's thoughts, feelings, or behaviors deviating from their level on a given trait does not invalidate the existence of that trait. Some have highlighted this condition when acknowledging that traits will reveal themselves differently depending on the situation in which one resides (Funder, 2008), and we need to focus on consistency in thoughts, feelings, and behaviors across similar situations rather than across all situations (Roberts, 2009). Others have suggested that traits are a distribution of states (Fleeson, 2001); thus, there will be deviations from trait-level (or mean state-level in the distribution) regardless of the situation in which an individual is (Fleeson, 2004). At this point, traits have been described as a sum of habits, which are a sum of states (Allemand & Flückiger, 2017); even as states deviate from traits, traits are still strong predictors of an individual's most frequent states (Fleeson & Gallagher, 2009). Thus, Allport (1931) was correct in asserting that a deviating act is "not proof of the non-existence of the trait," (p. 371). In fact, over three decades later, Allport (1966) notes, "the variability of behavior cannot be overlooked… I have learned that my earlier views seemed to neglect the variability induced by ecological, social, and situational factors. This oversight needs to be repaired through an adequate theory that will relate the inside and outside systems more acutely," (p. 9).
The way this criterion fits into the purpose literature can be tricky given the lack of work on short-term sense of purpose variability. One of the only studies that has considered daily sense of purpose levels found that certain engaging in certain activities (like assisting one's family members) and avoiding others (like less leisure time) were associated with greater daily sense of purpose in adolescents (Kiang, 2012); however, this study did not evaluate the extent to which daily sense of purpose was associated with trait-level sense of purpose, or how the proportion of variability decomposed at the within-versus between-person level. Some work looking at daily sense of purpose during the COVID-19 pandemic found that half of the variance in daily purposefulness was between-person and the other half withinperson (Hill, Klaiber, et al., 2021). Another study using a measurement burst design found that the variability in daily sense of purpose is greater between-people than within-people (Pfund, Hofer, et al., 2021). Furthermore, this work found that these amount of daily withinperson variability was consistent across bursts, meaning that people were consistent across a year in how much variability they experienced from one day to the next. Thus, there is evidence for both within-and between-person variability in short-term sense of purpose levels, though initial evidence points to consistency in variability within individuals over time. Though this particular question is one the requires more research, the research that exists aligns with Allport's (1931) general point that "there are in every personality instances of acts that are unrelated to existent traits" (p. 371). In the case of sense of purpose, these instances are not so great as to prove the trait does not exist.

Sense of Purpose is Within and Between
The final trait criterion which Allport (1931) puts forth is that "a trait may be viewed either in the light of the personality which contains it, or in the light of its distribution in the population at large," (p. 372). Thus, the presence of a trait can vary within an individual, or a trait can be viewed as something between individuals, even though it may not exist within every individual. These distinctions, which Allport (1931) describes as a "unique aspect" versus a "universal aspect" (p. 372), align with the idiographic and nomothetic perspectives put forth in personality psychology (Barenbaum & Winter, 2008). Idiographic approaches to personality focus on the structure of traits within an individual (Beck & Jackson, 2020), while more commonly used nomothetic approaches focus on between-person differences (Barenbaum & Winter, 2008). Currently, most quantitative research on sense of purpose has taken a more nomothetic perspective by considering at what points in the lifespan we can anticipate seeing differences on purpose (Bronk et al., 2009;Hedberg et al., 2011;Hill & Weston, 2019), as well as the outcomes associated with between-person differences on this trait (Boyle, Barnes, et al., 2009;Hill, Sin, et al., 2018;Kim, Sun, et al., 2013a).
Little purpose research has taken a quantitatively idiographic approach when understanding this construct. Work investigating the implications for daily purposeful pursuits on affective well-being, meaning in life, and self-esteem found that some of these associations differed based on whether someone has social anxiety disorder (Kashdan & McKnight, 2013), highlighting the potential for structural differences with this construct. Furthermore, qualitative work has highlighted that some older adults do not view purpose as having a role at that stage in their life . Though focused on people's opinions of purpose rather than the presence of sense of purpose in their lives, this findings may connect to Allport's (1931) suggestion that there are likely few traits which will be present in all individuals. Individuals identify as having different purposes in life (i.e., purpose orientations; Hill, Burrow, et al., 2010), though their reported sense of purpose levels may be the same. Given that the activities to pursue one's purpose in life necessarily differ based on those overarching goals (McKnight & Kashdan, 2009), another consideration is the presence of sense of purpose within individuals may not differ so much as their enaction of purposeful thoughts, feelings, and behaviors (see Hill et al., 2023). Relatedly, there has been recent recognition that the content which promotes one's sense of purpose may function differently between people when considering the broader context in which individuals reside . While the opportunities for research on this question regarding the more nuanced, idiographic nature of sense of purpose remains, there is vast evidence to support the nomothetic existence of this trait. Allport (1931) created a clear roadmap for evaluating whether a construct can be considered a trait. Sense of purpose meets the demands for most of the criteria set forth, such as illustrating that it "has more than a nominal existence" (Allport, 1931, p. 368), and that it has been "established empirically or statistically," (Allport, 1931, p. 369). Some of the conclusions about whether sense of purpose is a trait may differ depending on how one conceptualizes it, like when considering whether it "is not the same as a moral quality," (p. 371); hence, the sense of purpose definition I put forth in the current paper is one removed from some with more value-laden tendencies. Finally, some of Allport's (1931) suggested criteria require further research, like his final point about traits having both "its unique and universal aspects," (p. 372). However, this point acknowledges the nuances surrounding traits rather than providing a more stringent hurdle over which trait researchers must jump. Though some of the criteria may require further research, sense of purpose generally aligns with many of the criteria established in Allport's (1931) trait theory, thus providing another individual difference to add to the collection for personality researchers to consider beyond the Big Five.

Conclusion
A broader goal in this classification is to better understand the changeability of sense of purpose. Sense of purpose predicts positive outcomes throughout the lifespan (Pfund, 2020), while also being less salient in younger and older adults (Mann et al., 2021;Pinquart, 2002). Thus, the classification of this powerful construct also provides a guiding framework for both the obstacles and promises ahead as we uncover how to make sense of purpose more accessible to all. While personality researchers have explored interventions efforts to change traits (e.g., Hudson, Fraley, et al., 2021;Stieger, Flückiger, et al., 2021), the longterm efficacy and predictive implications of these interventions are still under investigation.
Given the uphill battle with intervening on traits, some may wonder why I am seeking to classify sense of purpose as a trait. When responding to others' disbelief of the existence of traits, Allport (1966) deems the common examples his critics call upon to disprove and mark their concerns of the reality of traits "the fallacy of misplaced concreteness," (p. 1). In particular, he describes their concerns over statements of behaviors like "John behaves aggressively," to spiral to the bigger claim of, "John has a trait of aggression," (p. 1). In this case, Allport (1966) is explaining to his adversaries that claiming something to be a trait does not cause it to become one. The current predicament with whether sense of purpose is a trait could be considered the reverse of this scenario: the fallacy of misplaced ephemerality.
Thus, to those confused with the current work's exploration, I will point out that the nature of sense of purpose will not transform based on how we categorize it. Instead, our categorization will shift our perceptions surrounding challenges in intervening upon it. By taking a more conservative and, perhaps, daunting approach in classifying sense of purpose as a trait, researchers invested in interventions will regard the changeability of this construct with more humility and caution, which, in turn, will lead to more rigorous, thoughtful, and empirically-driven intervention efforts. To support individuals in bolstering their sense of purpose is the goal, and correctly categorizing it will guide our paths in more effectively accomplishing that goal.