A New Vision for High-Quality Preschool Curriculum (2024)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

EVIDENCE ON THE EFFECTIVENESS OF PRESCHOOL CURRICULA 2-1 2 Evidence on the Effectiveness of Preschool Curricula Decades of research has shown that attending preschool (versus staying home with a family member) better prepares young children for kindergarten, with effects sometimes lasting into adulthood on important outcomes such as educational attainment and health (Heckman & Karapakula, 2019a, 2019b; Phillips et al., 2017b; Reynolds, Ou, & Temple, 2018; Yoshikawa et al., 2013). However, preschool programs are not equally effective; some children appear to learn more in some programs than others (Phillips et al., 2017). Accordingly, research has recently turned to examining the specific components that drive children’s early learning gains in preschool programs (Weiland, 2018). One motivating factor for this shift has been extensive evidence that most public preschool programs are on average mediocre in their instructional quality, although they tend to score in the “good” range on organization, emotional climate, and structural factors (Burchinal, 2018; Weiland & Guerrero Rosada, 2022). Further, and troubling with regard to equity, the programs attended by children from marginalized groups score lower on a range of quality metrics compared with those attended by their peers, and they rarely include languages other than English (Latham et al., 2021; Valentino, 2018; Weiland et al., 2022). Curriculum has emerged as one particularly potent component with the potential to move the needle on the stubbornly mediocre instructional quality of most public preschool programs, particularly those that disproportionately serve children from minoritized backgrounds (Chaudry et al., 2021). Overall, research on the effects of preschool curricula on classroom processes and young children’s learning is deep and broad. In curriculum evaluation studies, “curriculum effectiveness” is determined by comparing the outcomes for children who participate in a particular curriculum with the outcomes for similar children who did not participate in that curriculum (i.e., the control condition). The difference in outcomes between the two groups is described as the “average effect” of the curriculum. Multiple recent reviews and meta-analytic studies have summarized average effects of preschool curricula (e.g., Chamber et al., 2016; Jenkins et al., 2018; Phillips et al., 2017b; Yoshikawa et al., 2013), and this remains an active area of research, with studies of newer curricula and follow-up longitudinal studies into elementary school and beyond currently under way (e.g., Maier et al., 2022; Sarama et al., 2017). Important questions, however, remain unanswered. Given the diversity of early education settings, educators, and children, it is important to look not just at “average effects” of curriculum but also at the specific contexts and conditions under which curricula can succeed, as well as for which students (Weiss et al., 2014). Variation in curriculum effects is important if the size of the average difference between children who did and did not experience the curriculum differs systematically across groups of students, settings, delivery approaches, and outcomes. For Prepublication Copy, Uncorrected Proofs 

EVIDENCE ON THE EFFECTIVENESS OF PRESCHOOL CURRICULA 2-2 example, a curriculum may be found to have a small average effect in improving students’ early literacy skills, but the magnitude of the effect may vary substantially by preschool setting (e.g., Head Start versus child care center), by the experience of the educator delivering the curriculum, or by students’ home language experiences and the outcomes measured. From a policy perspective, understanding variation in curriculum effects is important because decision makers are often asked to make choices about the curriculum approaches that will best serve their communities and narrow early opportunity gaps for historically marginalized children. If the effects of curricula vary, there may not be a “one-size-fits-all” approach for choosing a preschool curriculum. Decision makers therefore need evidence about the extent to which curriculum effects vary, and the types of curricula that would be most effective for their specific settings, teachers, and students. Ideally, the curricula chosen will promote the learning of all students and will build on the strengths of children from diverse backgrounds. This chapter reviews what is known about the effects of preschool curriculum, with a focus on how effects vary across several important dimensions, including curriculum type, outcomes used for assessing efficacy, student characteristics, teacher characteristics, preschool settings, and broader macro conditions. The chapter concludes with a discussion of gaps in the current evidence base and key conclusions that support the committee’s recommendations for moving the field forward. CURRICULUM TYPE Curriculum is defined in this report as a cohesive set of principles, learning goals, intentional teaching strategies, activities, experiences, and materials designed to help children learn and thrive. The effects of preschool curricula may depend on the content included in a specific curriculum, as well as how it is delivered in different preschool settings. For example, effects may vary with the content or foci of the curriculum; on the pedagogical approaches used for teaching content or lessons; on the types of support materials available for implementing the curriculum, including professional development for teachers; and on the levels or intensity at which the curriculum is delivered. The effect of a curriculum will also depend on what the curriculum is being compared against (the control condition) and on what is defined as an outcome and how it is measured. One important dimension on which preschool curricula vary is whether they purport to cover all developmental domains or a subset (see Chapter 1). The most widely used curricula in publicly funded preschool programs tend to do the former, spanning language, literacy, mathematics, social-emotional skills, executive functioning, and motor skills, and sometimes science and social studies (Jenkins & Duncan, 2017). These curricula are commonly referred to in the field as comprehensive, “whole child,” or “global” curricula. In contrast, preschool curricula that cover a subset of developmental domains tend to be referred to as “domain-specific curricula” or “supplemental curricula.” They are meant to be implemented for a portion of the child’s day, with other curricula covering the rest of the day (and other domains). The most successful of these curricula tend to have been developed by experts in the particular domains (Weiland et al., 2018; Yoshikawa et al., 2013). An example is a curriculum focused specifically on math or social-emotional skills. Prepublication Copy, Uncorrected Proofs 

EVIDENCE ON THE EFFECTIVENESS OF PRESCHOOL CURRICULA 2-3 Another important feature of curriculum and a key distinction between some comprehensive and domain-specific curricula is scope and sequence, that is, whether the curriculum includes activities to be carried out in a particular order, to match children’s developmental trajectories, or whether the teacher is meant to choose the order. Domain-specific curricula with the strongest track record have a specific scope and sequence intended to accord with the science of children’s development and learning in the target area (Weiland et al., 2018; Yoshikawa et al., 2013). The same is true for some comprehensive curricula as well, such as The HighScope Preschool Curriculum, The Creative Curriculum, and Connect4Learning (NCECDTL, 2020; Sarama et al., 2017). Rigorous studies conducted over the last 15 years have provided evidence on the effectiveness of these various curricular approaches (Phillips et al., 2017). In some of these studies, classrooms or schools were randomized to implement a specific comprehensive curriculum versus business as usual (often teacher-created curricula), while in others, classrooms or schools were randomized to implement a domain-specific curriculum versus business as usual (a comprehensive curriculum lacking a specific scope and sequence and/or a teacher-created curriculum). Analyses of these studies have found some evidence that comprehensive curricula sometimes have positive effects on the quality of classroom interactions and in some outcome domains (e.g., Jenkins et al., 2018; Fantuzzo, 2011). In comparisons of domain-specific and comprehensive curricula, the evidence tends to show no difference in general interactions in the classroom, but marked differences in instruction related to the skill area targeted by the domain- specific curriculum and positive impacts on child learning in that area. For example, multiple studies have found that math-specific curricula lead to increased time on and quality of math- specific learning in preschool classrooms and improve children’s math learning (Clements et al., 2023; Jenkins et al., 2018; Mattera et al., 2018; Wakabayashi et al., 2020). Interestingly, a study using five different large-scale data sets found that classroom scores on literacy, math, and quality of interactions varied just as widely for classrooms using the two most widely used comprehensive curricula in public preschool programs—HighScope and The Creative Curriculum—as for classrooms using no published curriculum (Jenkins et al., 2019). The evidence is also clear that domain-specific curricula following a specific scope and sequence have generally been more successful in improving targeted child outcomes relative to comprehensive or teacher-created curricula (Clements et al., 2023; Jenkins et al., 2018; Mattera et al., 2018; Phillips et al., 2017; Wakabayashi et al., 2020; Yoshikawa et al., 2013). Less evidence is available from settings outside the United States, but similar patterns in child outcomes have been shown (e.g., Arbour et al., 2023 in Chile; Rege et al., 2021 in Norway). Of course, a practical challenge for programs is they are not charged with promoting children’s learning and development in just one area or domain, nor do domain-specific curricula cover a full school day. Accordingly, some localities have combined domain-specific curricula. For example, Boston’s public pre-K program combined a language and literacy–focused curriculum with a math curriculum (Weiland & Yoshikawa, 2013), and rural Head Start centers in Pennsylvania had success combining a social-emotional curriculum with a literacy curriculum (Bierman et al., 2008). Notably, too, some domain-specific curricula have produced effects on outcomes other than those directly targeted. For example, the Building Blocks math curriculum Prepublication Copy, Uncorrected Proofs 

EVIDENCE ON THE EFFECTIVENESS OF PRESCHOOL CURRICULA 2-4 has shown positive effects on both executive functioning and language (Clements et al., 2023; Sarama et al., 2012; Weiland & Yoshikawa, 2013). The literature in this area has several limitations, however. To the committee’s knowledge, none of the curricula that have been rigorously studied to date have been evaluated for whether they were designed and implemented to be culturally and linguistically responsive to the children in the study sample. Nor is there much research on the effects of curricula when implemented in family child care homes. Further, it is standard practice in the field to use common measures to enhance cross-study comparability (Schneider, 2020; Slavin, 2019). But this is one of the many reasons why the research in this area has neglected effects on important outcomes such as the development of children’s home language among multilingual learners and skills that are more difficult to measure, such as creativity, positive identity, curiosity, and problem solving. The committee also found a troubling lack of information on the effects of curricula on such outcomes as children’s explicit bias, sense of belonging, agency, and group pride, as well as teacher outcomes such as bias, expectations for children from different backgrounds, and differential discipline based on children’s demographic characteristics. This is in part because there are very few measures of these outcomes and those that do exist lack the psychometric evidence for validity that tends to characterize frequently used measures of children’s academic and social-emotional skills. These limitations (and others) are discussed further at the end of this chapter and throughout this report. OUTCOMES USED FOR ASSESSING EFFECTIVENESS As described throughout this report, curricula vary in the classroom and child outcomes they target. Further, studies of even the same curricula vary as to which outcomes and measures were used to assess curricular effects on classroom processes and child learning. Also critical in understanding variation by outcome is the nature of the construct or skill at hand. For example, preschoolers tend to master narrower skills, such as letter knowledge and print awareness, more quickly than broader skills or more domain general skills that support development in multiple areas, such as vocabulary and productive language (McCormick et al., 2021). Even within the same domain, effects can vary depending on how narrow the skill addressed by a particular assessment is. For example, preschoolers are likely to show much larger effects on a vocabulary assessment of 15 words taught specifically in a curriculum than on overall vocabulary assessment of all the words the child knows. Indeed, the empirical literature commonly shows much larger effects of preschool programs and specific curricula on narrower, domain-specific versus broader, domain general child skills (Goodrich et al., 2017; Gormley et al., 2005; Weiland & Yoshikawa, 2013; Wong et al., 2008). This is not to suggest a hierarchy of skill types, in which some are more important than others. Both narrower and broader skills are foundational for children’s learning and later school success (McCormick et al., 2021). Further, learning is cumulative; skills in one area can support the development of skills in other areas (Weiland, Barata, & Yoshikawa, 2016; Blair & Razza, 2007; Clements et al., 2016). Nonetheless, in assessing variation in the effects of curricula, it is critical to differentiate which skills are more malleable than others in the short term. Prepublication Copy, Uncorrected Proofs 

EVIDENCE ON THE EFFECTIVENESS OF PRESCHOOL CURRICULA 2-5 With regard to effects of curricula on classroom processes, the literature shows less of a pattern of variation in curriculum effects based on which outcome measure is chosen. This is in part due to the fact that preschool curriculum studies tend to use fewer common classroom-level process measures than child-level measures, making findings more difficult to compare across studies. Measures in these studies include observational measures of curriculum fidelity, measures of the global quality of teacher–child interactions at the classroom level, domain- specific quality of instructional practices measures, time-use measures, and a combination of these (Nesbitt & Farran, 2021; Watts et al., 2018; Weiland & Guerrero Rosada, 2022). Further, it is not uncommon to see relatively large impacts on classroom process outcomes and null effects on children’s learning (Howard et al., 2021; Jenkins et al. 2018; Yoshikawa et al., 2015). STUDENT CHARACTERISTICS Even if an intervention is implemented with the same intensity and quality, it may be more effective for some groups and in some contexts than others (Weiss et al., 2014; Steiner et al., 2019). Subgroup effects for preschool curricula have been less well studied than average effects, in part because of sample size requirements. Often, limited resources or other practical constraints make it difficult to have enough sites, teachers, and children for a well-powered test of the average effect of a curriculum, let alone to examine variation in effects by subgroups. This limitation is important in the context of this study because a curriculum that promotes equity for marginalized groups will ideally benefit all children’s learning, but especially that of children from marginalized groups. Preschool attendance, for example, appears to have greater benefits for multilingual learners and children from families with low incomes than for their peers compared with other care options in the year before kindergarten (Phillips et al., 2017b; Yoshikawa et al., 2013). In reviewing sources of moderation (i.e., whether effects differ by child characteristics), the committee drew on studies that examined the question of moderators through formal testing where possible, but also on studies conducted primarily with a marginalized group. The committee’s rationale for doing so was the assumption that if a curriculum study was conducted in Head Start, it could presumably inform discussion of effects for children from families with low incomes, even if the research team could not test whether these effects were greater than those for children from families with higher incomes because they were not enrolled in Head Start. Many preschool curriculum studies have been conducted in income-targeted publicly funded programs and for this reason, with disproportionate samples of minoritized children. Overall, evidence is mixed for studies that have tested whether curriculum effects differ by child characteristics. For example, some studies found no differences by family income (Clements & Sarama, 2012); gender identity (Clements & Sarama, 2008; Dumas et al., 2019; Nesbitt & Farran, 2021; Weiland & Yoshikawa et al., 2013); child race/ethnicity (Sarama et al., 2008); disability (Clements et al., 2012; Nesbitt & Farran, 2021); or language status (McCarthy et al., 2015; Nesbitt & Farran, 2021). In other words, these groups appear to have experienced the same curriculum effects as their peers. Other studies, however, did find differences in curriculum effects by these demographic characteristics. For example, effects of the Building Blocks math curriculum were greater for Prepublication Copy, Uncorrected Proofs 

EVIDENCE ON THE EFFECTIVENESS OF PRESCHOOL CURRICULA 2-6 Black and Latino children than for their White peers in multiple trials (Clements et al., 2011; Clements et al., 2012; Dumas et al., 2019; Weiland & Yoshikawa, 2013). Multiple studies have found greater effects for multilingual learners than for their monolingual peers on English oral language outcomes, typically in studies with language- and literacy-focused curriculum compared with business-as-usual comprehensive curriculum approaches (Kaiser et al., 2011; Wilson et al., 2013). Some curricula also show greater effects for children who begin the preschool year with lower skills than their peers. For example, two studies of the Building Blocks math curriculum found that children with lower baseline math skills gained more in their math skills in the preschool year (Mattera et al., 2021; Watts et al., 2018). Studies of social- emotional curriculum have found greater gains in students with lower baseline skills (Finlon et al., 2015; Flook et al., 2015), but also greater gains in students with higher baseline skills (Shea & Jenkins, 2021). Overall, drawing firm conclusions for particular groups or within specific contexts across preschool curriculum studies is challenging for three reasons: (1) most studies were underpowered for detecting subgroup differences; (2) some of the detected differences may have been due to chance (i.e., the multiple comparisons problem; Schochet, 2009); and (3) standardized reporting is lacking, hindering interpretation of these findings. Nonetheless, taken together, these studies point to the potential for curricula, particularly some domain-specific curricula, to have greater effects for marginalized groups, although more research in this area is needed, a point we return to at the end of this chapter and in Chapter 10. TEACHER CHARACTERISTICS The early care and education workforce is highly diverse with respect to professional training and development as a result of the fragmented early learning landscape and chronic under investment in the United States (Chaudry et al., 2021). Some of these teachers complete the kinds of preparatory programs common among teachers in grades K–12, which include a bachelor’s degree (or higher), student teaching, and formal certification. Others, however, have more minimal preparation when they begin and gain their training largely on the job. Research is mixed on the degree to which teacher qualifications promote children’s learning (Early et al., 2007; IOM and NRC, 2015; Lin & Magnuson, 2018). For in-service teachers, training and in- classroom coaching can promote children’s learning, but generally has been found to do so only when tied to the implementation of a domain-specific curriculum and not general best teaching practices (Pianta et al., 2017; Piasta et al., 2017; Weiland et al., 2018; Yoshikawa et al., 2013; Yoshikawa et al., 2015). To move the needle on classroom processes and child learning, a preschool curriculum must be implementable at a high level of quality by teachers with a wide range of preparation and skills. Alternatively, the curriculum should be targeted only to teachers for whom it is well matched in terms of preparation. Very few studies have explicitly tested whether curriculum effects on classroom processes and child learning vary by teacher characteristics, such as training/education or language proficiency. This is the case in part because teacher characteristics in a given setting may not vary much. For example, if a curriculum is being tested in a public preschool system that requires at least a bachelor’s degree, researchers cannot test whether effects are different for Prepublication Copy, Uncorrected Proofs 

EVIDENCE ON THE EFFECTIVENESS OF PRESCHOOL CURRICULA 2-7 teachers with less educational attainment. Issues of statistical power are at play here, too, just as they are for child characteristics. Accordingly, some of the best evidence comes from comparisons across different studies rather than from within-study comparisons. Domain-specific curricula, when supported by training and coaching, for example, have shown positive effects on classroom processes and child learning in settings where teachers have both lower educational levels (Bierman et al., 2008; Morris et al., 2014) and relatively higher educational levels (Weiland & Yoshikawa, 2013). At least one comprehensive curriculum, in contrast, showed some benefits for classroom processes but none for child learning gains, in a context in which most teachers had a bachelor’s degree (Howard et al., 2021). Another literature examines whether curricula are more readily implemented by teachers with different background characteristics and professional preparation. For example, a study of 74 mostly White (92%) and female (96%) teachers in Head Start and public pre-K in rural Appalachian communities found high rates of high implementation fidelity for a domain-specific language and literacy curriculum, regardless of teacher education (34% had an associate’s degree or lower; 39% a bachelor’s degree; and 23% a master’s degree [Piasta et al., 2015]). Similar results were found in a study of a vocabulary and language curriculum in which teachers’ preparedness and classroom management predicted their implementation fidelity, but their education levels did not (Phillips et al., 2017a). Underscoring the importance of fidelity, some studies have found that fidelity of implementation predicted children’s gains in preschool math (Sarama et al., 2008), language and literacy (Hamre et al., 2010), and curriculum focused on multiple domains (Maier et al., 2022b). Taken together, a broad range of early educators appear to be capable of implementing different preschool curricula. Teacher degrees, for example, do not appear to be decisive with regard to quality or fidelity of implementation. However, this finding is difficult to test given the fragmented nature of the U.S. education landscape and the fact that rigorous evidence in this area is limited. PRESCHOOL SETTING Preschool is delivered in a range of settings, including family child care homes, community-based preschool classrooms, for-profit preschools, faith-based schools, charter schools, and traditional public schools (Chaudry et al., 2021). Much of the time, curriculum trials are conducted within one of these settings. For example, trials might be carried out entirely within Head Start sites (e.g., Morris et al., 2014) or within public preschool classrooms in traditional public schools (e.g., Clements et al., 2011). When trials are limited to one setting, curriculum effectiveness can be examined across settings only with cross-study comparisons. Some studies of curriculum, however, have included a mix of setting types—for example, in Head Start, public schools, and other community-based organizations (CBOs), as in a recent trial of the HighScope curriculum (Howard et al., 2021) or in CBOs and public schools, as in a recent trial of the Building Blocks math curriculum (Mattera et al., 2018). Here, overall, the evidence base is similar to that for teachers with different characteristics, given the often substantial sorting of teachers into settings by their qualifications Prepublication Copy, Uncorrected Proofs 

EVIDENCE ON THE EFFECTIVENESS OF PRESCHOOL CURRICULA 2-8 (Weiland et al., 2022). For example, the evidence shows that teachers in CBO, Head Start, and public school settings can implement curricula at least moderately well (Yoshikawa et al., 2013). When a study covers multiple settings, researchers do sometimes examine moderation of effects on classroom processes and child learning outcomes by setting. However, this practice is uncommon because of issues of statistical power. The available research shows some evidence of differential preintervention processes and differential effects of curriculum on both classroom processes and child learning by setting. As one example, a recent study found that preintervention, CBO classrooms spent less time on math instruction and had lower-quality math instruction at baseline compared with public schools. A math-specific curriculum increased the amount of time children spent in math in both settings; children’s math skills improved in public schools and their vocabulary and executive function in CBO settings (McCormick et al., 2022). Setting characteristics are another important source of potential variation in effects that is underexplored in the literature. For example, some preschools are full day, while others are half- day. Interestingly, a previous study of Tulsa’s pre-K program found greater effects of the half-day program than for the full-day program, although children’s characteristics were confounded by program type in that study (Gormley et al., 2005). A recent randomized trial of half- versus full- day programs in a context that implemented a domain-specific literacy curriculum found greater effects of full-day instruction on children’s learning (Atteberry et al., 2019). Critically, there has been almost no rigorous research on preschool curriculum in family child care homes, for-profit preschools, faith-based schools, or charter schools—another gap to which we return at the conclusion of this chapter and throughout the report. MACRO CONDITIONS Changes in the macro context may affect the size of curriculum effects; such changes include, for example, broader economic conditions, workforce policies, and shifts in parenting practices and children’s skills over time that can influence child development. Broader economic changes such as economic growth and downturns have been shown to affect community- and family-level factors that in turn influence child development (Weiland & Yoshikawa, 2012). Regarding the workforce, preschool teachers, for example, are frequently paid far less than their K–12 peers, which helps fuel teacher turnover (Chaudry et al., 2021). Curricula may be less effective accordingly in settings in which teachers are trained and then leave as opposed to settings with more workforce stability. Regarding shifts in parenting practices, there is evidence that between the late 1990s and 2010, parents of young children exposed them to more books and educational games in the home and engaged more with their children, with the largest increases among parents with low incomes (Bassok et al., 2016). Over this same period, young children, particularly Black children, were entering kindergarten with stronger teacher-reported math and literacy skills (Bassok & Latham, 2017). Other evidence shows that the type of parent–child home learning activities affects children’s gains in the preschool year (McCormick et al., 2020). Home learning activities also vary by family background; for example, Latine families in the United States are more likely to emphasize animals in science conversations with their children and to use mealtimes for rich family conversations (Leyva et al., 2022). Prepublication Copy, Uncorrected Proofs 

EVIDENCE ON THE EFFECTIVENESS OF PRESCHOOL CURRICULA 2-9 Taken together, these shifts mean curricula are supporting children whose experiences differ from those of their counterparts a generation ago. To our knowledge, there is no direct evidence on how macro shifts may have affected the findings of research on preschool curriculum. Nonetheless, this potential source of evidence is important as a lens for interpreting those findings, particularly when comparing trials from the early 2000s with today’s evidence. CONCLUSION As summarized in the chapter, the available research shows that preschool curriculum can be a potent means of moving the needle on instructional quality, classroom processes, and children’s early learning, particularly for children from marginalized groups. Effects of preschool curricula can vary by curriculum type, outcomes used to assess effects, and student characteristics; to a lesser degree, effects can vary by teacher characteristics, preschool setting, and broader macro conditions. However, important, unanswered questions remain about the effects of culturally responsive curricula; effects of curricula in family child care, for-profit, charter school, or faith-based school contexts; effects on less commonly measured child outcomes, such as creativity, problem solving, child healthy racial identity, multilingual learners’ growth in home language as well as English language development, and bias; and effects of widely adopted instructional approaches to preschool, such as Montessori, project-based learning, and Reggio Emilia (see chapter 4 for a more detailed discussion of these approaches). Realizing a new vision for preschool curriculum will require prioritizing and answering these questions. It will also require new approaches to translating evidence on curriculum into policy and practice. Thus far, the large evidence base on preschool curricula appears to have had little influence on the curriculum choices of public preschool programs. For example, these programs overwhelmingly use comprehensive curricula that, compared with domain-specific curricula, have been found to have smaller gains in domain-targeted academic (Jenkins & Duncan, 2017). A key challenge in moving the field forward on a new vision for curriculum that reflects the developmental strengths of children and families and is more inclusive of cultural and linguistic variations—particularly for the children with the least access to opportunity—is developing policy levers for curriculum choice and use that are more closely tied to the evidence base. These policy levers could include allocating additional public funding to incentivize programs to use evidence-based curricula; providing quality improvement supports and resources to address equity and inclusion gaps; and providing technical assistance and targeted funding to support ongoing professional development related to incorporating evidence-based curricula. REFERENCES Arbour, M., Soto, C., Alée, Y., Atwood, S., Muñoz, P., & Marzolo, M. (2023). Absenteeism prevention in preschools in Chile: Impact from a quasi-experimental evaluation of 2011–2017 Ministry of Education data. In Frontiers in Education (Vol. 7, p. 975092). Frontiers Media SA. doi: 10.3389/feduc.2022.975092 Prepublication Copy, Uncorrected Proofs 

EVIDENCE ON THE EFFECTIVENESS OF PRESCHOOL CURRICULA 2-10 Atteberry, A., Bassok, D., & Wong, V. C. (2019). The effects of full-day prekindergarten: Experimental evidence of impacts on children’s school readiness. Educational Evaluation and Policy Analysis, 41(4), 537-562. https://doi.org/10.3102/0162373719872197 Bassok, D., Finch, J. E., Lee, R., Reardon, S. F., & Waldfogel, J. (2016). Socioeconomic gaps in early childhood experiences: 1998 to 2010. Aera Open, 2(3), 2332858416653924. https://doi.org/10.1177/2332858416653924 Bassok, D., & Latham, S. (2017). Kids today: The rise in children’s academic skills at kindergarten entry. Educational Researcher, 46(1), 7-20. https://doi.org/10.3102/0013189X17694161 Bierman, K. L., Domitrovich, C. E., Nix, R. L., Gest, S. D., Welsh, J. A., Greenberg, M. T., ... & Gill, S. (2008). Promoting academic and social‐emotional school readiness: The Head Start REDI program. Child Development, 79(6), 1802-1817. https://doi.org/10.1111/j.1467-8624.2008.01227.x Blair, C., & Razza, R. P. (2007). Relating effortful control, executive function, and false belief understanding to emerging math and literacy ability in kindergarten. Child development, 78(2), 647- 663. https://doi.org/10.1111/j.1467-8624.2007.01019.x Burchinal, M. (2017). Measuring Early Care and Education Quality. Child Development Perspectives, 12, 3-9. https://doi.org/10.1111/cdep.12260 Chaudry, A., Morrissey, T., Weiland, C., & Yoshikawa, H. (2021). Cradle to Kindergarten: A new plan to combat inequality (Second edition). New York, NY: Russell Sage. Chambers, B., Cheung, A. C., & Slavin, R. E. (2016). Literacy and language outcomes of comprehensive and developmental-constructivist approaches to early childhood education: A systematic review. Educational Research Review, 18, 88-111. https://doi.org/10.1016/j.edurev.2016.03.003 Clements, D. H., & Sarama, J. (2008). Experimental evaluation of the effects of a research-based preschool mathematics curriculum. American Educational Research Journal, 45, 443-494. https://doi.org/10.3102/0002831207312908 Clements, D. H., Sarama, J., & Germeroth, C. (2016). Learning executive function and early mathematics: Directions of causal relations. Early Childhood Research Quarterly, 36, 79-90. https://doi.org/10.1016/j.ecresq.2015.12.009 Clements, D. H., Sarama, J., Spitler, M. E., Lange, A. A., & Wolfe, C. B. (2011). Mathematics learned by young children in an intervention based on learning trajectories: A large-scale cluster randomized trial. Journal for Research in Mathematics Education, 42(2), 127-166. https://doi.org/10.5951/jresematheduc.42.2.0127. Clements, D. H., Sarama, J., Wolfe, C. B., & Spitler, M. E. (2013). Longitudinal evaluation of a scale-up model for teaching mathematics with trajectories and technologies: Persistence of effects in the third year. American Educational Research Journal, 50, 812-850. https://doi.org/10.3102/0002831212469270 Dumas, D., McNeish, D., Sarama, J., & Clements, D. (2019). Preschool mathematics intervention can significantly improve student learning trajectories through elementary school. AERA Open, 5, 2332858419879446. https://doi.org/10.1177/2332858419879446 Early, D. M., Maxwell, K. L., Burchinal, M., Alva, S., Bender, R. H., Bryant, D., Cai, K., Clifford, R. M., Ebanks, C., Griffin, J. A., Henry, G. T., Howes, C., Iriondo-Perez, J., Jeon, H-J., Mashburn, A., J., Peisner- Feinberg, E., Pianta, R. C., Vandergrift, N., & Zill, N. (2007). Teachers' education, classroom quality, and young children's academic skills: Results from seven studies of preschool programs. Child Development, 78(2), 558-580. https://www.jstor.org/stable/4139245 Finlon, K. J., Izard, C. E., Seidenfeld, A., Johnson, S. R., Cavadel, E. W., Ewing, E. S. K., & Morgan, J. K. (2015). Emotion-based preventive intervention: Effectively promoting emotion knowledge and adaptive behavior among at-risk preschoolers. Development and psychopathology, 27(4pt1), 1353- 1365. doi: 10.1017/S0954579414001461 Flook, L., Goldberg, S. B., Pinger, L., & Davidson, R. J. (2015). Promoting prosocial behavior and self- regulatory skills in preschool children through a mindfulness-based Kindness Curriculum. Developmental Psychology, 51, 44–51. https://doi.org/10.1037/a0038256 Prepublication Copy, Uncorrected Proofs 

EVIDENCE ON THE EFFECTIVENESS OF PRESCHOOL CURRICULA 2-11 Gilliam, W. S., Maupin, A. N., Reyes, C. R., Accavitti, M., & Shic, F. (2016). Do early educators’ implicit biases regarding sex and race relate to behavior expectations and recommendations of preschool expulsions and suspensions. Yale University Child Study Center, 9(28), 1-16. https://marylandfamiliesengage.org/wp-content/uploads/2019/07/Preschool-Implicit-Bias-Policy- Brief.pdf Goodrich, J. M., Lonigan, C. J., & Farver, J. A. M. (2017). Impacts of a literacy-focused preschool curriculum on the early literacy skills of language-minority children. Early Childhood Research Quarterly, 40, 13-24. https://doi.org/10.1016/j.ecresq.2017.02.001 Gormley Jr, W. T., Gayer, T., Phillips, D., & Dawson, B. (2005). The effects of universal pre-K on cognitive development. Developmental Psychology, 41, 872. https://doi.org/10.1037/0012- 1649.41.6.872 Hamrea, B. K., Justice, L. M., Pianta, R. C., Kilday, C., Sweeney, B., Downer, J. T., & Leach, A. (2010). Implementation fidelity of MyTeachingPartner literacy and language activities: Association with preschoolers’ language and literacy growth. Early Childhood Research Quarterly, 25(3), 329-347. https://doi.org/10.1016/j.ecresq.2009.07.002 Heckman, J. J. & Karapakula, G. (2019a). Intergenerational and intragenerational externalities of the Perry Preschool Project: NBER Working Paper No. 25889. Cambridge, MA: National Bureau of Economic Research. DOI:10.3386/w25889. https://www.nber.org/papers/w25889 Heckman, J. J., & Karapakula, G. (2019b). The Perry Preschoolers at late midlife: A study in design- specific inference (Working Paper No. 25888). Cambridge, MA: National Bureau of Economic Research. DOI 10.3386/w25888. http://www.nber.org/papers/w25888 Howard, E., Weinberg, E., Yee,D., Ogut, B., & Lee, D. (2021). HighScope preschool curriculum and professional development efficacy study: Results in brief. Washington, DC: American Institutes for Research. https://www.air.org/sites/default/files/HighScope-Results-in-Brief-Jan-2021.pdf Institute of Medicine (IOM) and National Research Council (NRC). 2015. Transforming the workforce for children birth through age 8: A unifying foundation. Washington, DC: The National Academies Press. Jenkins, J. M., & Duncan, G. J. (2017). Do prekindergarten curricula matter? In D. Phillips and K. Dodge (eds.). The Current State of Scientific Knowledge on Pre-Kindergarten Effects (pp.37-44). Washington, DC: Brookings Institute. Retrieved from https://www.researchgate.net/profile/Jade- Jenkins-6/publication/317904908_Do_pre- kindergarten_curricula_matter/links/595e50a9a6fdccc9b17fd2f2/Do-pre-kindergarten-curricula- matter.pdf Jenkins, J. M., Duncan, G. J., Auger, A., Bitler, M., Domina, T., & Burchinal, M. (2018). Boosting school readiness: Should preschool teachers target skills or the whole child? Economics of Education Review, 65, 107-125. https://doi.org/10.1016/j.econedurev.2018.05.001 Jenkins, J. M., Whitaker, A. A., Nguyen, T., & Yu, W. (2019). Distinctions without a difference? Preschool curricula and children’s development. Journal of Research on Educational Effectiveness, 12(3), 514-549. https://doi.org/10.1080/19345747.2019.1631420 Kaiser, A., Dickinson, D., Roberts, M., Darrow, C., Freiberg, J., & Hofer, K. (2011). The Effects of Two Language-Focused Preschool Curricula on Children’s Achievement through First Grade. Society for Research on Educational Effectiveness. Kelly, D. J., Quinn, P. C., Slater, A. M., Lee, K., Gibson, A., Smith, M., Ge, L. & Pascalis, O. (2005). Three‐month‐ olds, but not newborns, prefer their own‐race faces. Developmental Science, 8(6), F31- F36. https://doi.org/10.1111/j.1467-7687.2005.0434a.x Latham, S., Corcoran, S. P., Sattin-Bajaj, C., & Jennings, J. L. (2021). Racial disparities in pre-k quality: Evidence from New York City’s universal pre-k program. Educational Researcher, 50(9), 607-617. https://doi.org/10.3102/0013189X211028214 Lee, K., Quinn, P. C., & Pascalis, O. (2017). Face race processing and racial bias in early development: A perceptual-social linkage. Current Directions in Psychological Science, 26(3), 256- 262. https://doi.org/10.1177/0963721417690276 Prepublication Copy, Uncorrected Proofs 

EVIDENCE ON THE EFFECTIVENESS OF PRESCHOOL CURRICULA 2-12 Leyva, D., Weiland, C., Shapiro, A., & Yeomans-Maldonado, G. (2022). A strengths-based, culturally responsive family intervention improves Latino kindergarteners’ vocabulary and approaches to learning. Child Development, 93, 451-467. https://doi.org/10.1111/cdev.13698 Lin, Y. C., & Magnuson, K. A. (2018). Classroom quality and children’s academic skills in child care centers: Understanding the role of teacher qualifications. Early Childhood Research Quarterly, 42, 215-227. https://doi.org/10.1016/j.ecresq.2017.10.003 Maier, M., Hsueh, J., Somers, M., & Burchinal, M. (2022) Does classroom quality promote preschoolers’ learning? A conceptual framework for evaluating the impact of classroom quality on child outcomes. OPRE Report 2022-159. Washington, DC: Office of Planning, Research, and Evaluation, Administration for Children and Families, U.S. Department of Health and Human Services. https://www.acf.hhs.gov/opre/report/does-classroom-quality-promote-preschoolers-learning- conceptual-framework-evaluating Maier, M. F., McCormick, M. P., Xia, S., Hsueh, J., Weiland, C., Morales, A., Boni, M., Tonachel, M., Sachs, J., & Snow, C. (2022b). Content-rich instruction and cognitive demand in prek: using systematic observations to predict child gains. Early Childhood Research Quarterly, 60, 96-109. https://doi.org/10.1016/j.ecresq.2021.12.010 Mattera, S. K., Jacob, R., MacDowell, C., & Morris, P.A. (2021). Long-Term Effects of Enhanced Early Childhood Math Instruction: The Impacts of Making Pre-K Count and High 5s on Third-Grade Outcomes. New York, New York: MDRC. https://www.mdrc.org/publication/long-term-effects- enhanced-early-childhood-math-instruction Mattera, S., Jacob, R., & Morris, P. (2018). Strengthening children's math skills with enhanced instruction: The impacts of Making Pre-K Count and High 5s on kindergarten outcomes. MDRC: New York, New York. https://www.mdrc.org/publication/strengthening-children-s-math-skills- enhanced-instruction McCarthy, B., Li, L., Tiu, M., Atienza, S., & Sexton, U. (2015). Learning with PBS KIDS: A study of family engagement and early mathematics achievement. San Francisco, CA: WestEd. https://www.wested.org/resources/learning-with-pbs-kids/ McCormick, M. P., Mattera, S. K., Maier, M. F., Xia, S., Jacob, R., & Morris, P. A. (2022). Different settings, different patterns of impacts: Effects of a Pre-K math intervention in a mixed-delivery system. Early Childhood Research Quarterly, 58, 136-154. https://doi.org/10.1016/j.ecresq.2021.08.005 McCormick, M., Weiland, C., Hsueh, J., Pralica, M., Weissman, A., Moffett, L., Snow, C., & Sachs, J. (2021). Is skill type the key to the PreK fadeout puzzle? Differential associations between enrollment in PreK and constrained and unconstrained skills across kindergarten. Child Development, 92, 599- 620. https://doi.org/10.1111/cdev.13520 McCormick, M. P., Weissman, A. K., Weiland, C., Hsueh, J., Sachs, J., & Snow, C. (2020). Time well spent: Home learning activities and gains in children’s academic skills in the prekindergarten year. Developmental Psychology, 56(4), 710. https://doi.org/10.1037/dev0000891 Morris, P., Mattera, S. K., Castells, N., Bangser, M., Bierman, K., & Raver, C. (2014). Impact findings from the Head Start CARES Demonstration: National evaluation of three approaches to improving preschoolers’ social and emotional competence. Executive summary (OPRE Report No. 2014-44). Washington, DC: Office of Planning, Research and Evaluation. https://www.acf.hhs.gov/opre/report/impact-findings-head-start-cares-demonstration-national- evaluation-three-approaches National Center on Early Childhood Development, Teaching, and Learning. (2020). Preschool curriculum consumer report. Office of Head Start, U.S. Department of Health and Human Services. https://eclkc.ohs.acf.hhs.gov/sites/default/files/featured_file/preschool-curriculum-consumer-report- 032519.pdf Nesbitt, K. T., & Farran, D. C. (2021). Effects of prekindergarten curricula: Tools of the Mind as a case study. Monographs of the Society for Research in Child Development, 86(1), 7-119. https://doi.org/10.1111/mono.12425 Prepublication Copy, Uncorrected Proofs 

EVIDENCE ON THE EFFECTIVENESS OF PRESCHOOL CURRICULA 2-13 Pauker, K., Ambady, N., & Apfelbaum, E. P. (2010). Race salience and essentialist thinking in racial stereotype development. Child Development, 81(6), 1799-1813. https://doi.org/10.1111/j.1467- 8624.2010.01511.x Pianta, R., Hamre, B., Downer, J., Burchinal, M., Williford, A., Locasale-Crouch, J., Howes, C., La Paro, K., & Scott-Little, C. (2017). Early childhood professional development: Coaching and coursework effects on indicators of children’s school readiness. Early Education and Development, 28, 956-975. https://doi.org/10.1080/10409289.2017.1319783 Piasta, S. B., Justice, L. M., McGinty, A., Mashburn, A., & Slocum, L. (2015). A comprehensive examination of preschool teachers’ implementation fidelity when using a supplemental language and literacy curriculum. Child & Youth Care Forum 44, 731-755. Springer US. https://doi.org/10.1007/s10566-015-9305-2 Piasta, S. B., Justice, L. M., O'Connell, A. A., Mauck, S. A., Weber-Mayrer, M., Schachter, R. E., ... & Spear, C. F. (2017). Effectiveness of large-scale, state-sponsored language and literacy professional development on early childhood educator outcomes. Journal of Research on Educational Effectiveness, 10(2), 354-378. https://doi.org/10.1080/19345747.2016.1270378 Phillips, B. M., Ingrole, S. A., Burris, P. W., & Tabulda, G. (2017). Investigating predictors of fidelity of implementation for a preschool vocabulary and language curriculum. Early Child Development and Care, 187(3-4), 542-553. https://doi.org/10.1080/03004430.2016.1251428 Phillips, D. A., Lipsey, M. W., Dodge, K. A., Haskins, R., Bassok, D., Burchinal, M. R., Duncan, G. J., Dynarski, M., Magnuson, K. A., & Weiland, C. (2017). Puzzling it out: The current state of scientific knowledge on pre-kindergarten effects; a consensus statement. In The current state of scientific knowledge on pre-kindergarten effects (pp. 19–30). Washington, DC: Brookings Institution.https://www.brookings.edu/wp-content/uploads/2017/04/consensus-statement_final.pdf Rege, M., Størksen, I., Solli, I. F., Kalil, A., McClelland, M. M., ten Braak, D., Lenes, R., Lunde, S., Breive, S., Carlsen, M., Erfjord, I., & Hundeland, P. S. (2021). The effects of a structured curriculum on preschool effectiveness: A field experiment. Journal of Human Resources, 58(4). https://doi.org/10.3368/jhr.0220-10749R3 Sarama, J., Brenneman, K., Clements, D. H., Duke, N. K., & Hemmeter, M. L. (2017). Interdisciplinary teaching across multiple domains: The C4L (Connect4Learning) curriculum. In Implementing a standards-based curriculum in the early childhood classroom (pp. 1-53). New York, NY: Routledge. Sarama, J., Clements, D. H., Starkey, P., Klein, A., & Wakeley, A. (2008). Scaling up the implementation of a pre-kindergarten mathematics curriculum: Teaching for understanding with trajectories and technologies. Journal of Research on Educational Effectiveness, 1(2), 89-119. https://doi.org/10.1080/19345740801941332 Sarama, J., Lange, A. A., Clements, D. H., & Wolfe, C. B. (2012). The impacts of an early mathematics curriculum on oral language and literacy. Early Childhood Research Quarterly, 27(3), 489-502. https://doi.org/10.1016/j.ecresq.2011.12.002 Shea, Z. M., & Jenkins, J. M. (2021). Examining Heterogeneity in the Impacts of Social-emotional Curricula in Preschool: A Quantile Treatment Effect Approach. Frontiers in Psychology, 12, 1–16. Complementary Index. https://doi.org/10.3389/fpsyg.2021.624320 Schneider, M. (2020). Making common measures more common. Washington, DC: Institute of Education Sciences. https://ies.ed.gov/director/remarks/5-05-2020.asp Schochet, P. Z. (2009). An approach for addressing the multiple testing problem in social policy impact evaluations. Evaluation Review, 33(6), 539-567. https://doi.org/10.1177/0193841X09350590 Slavin, R. (2019). Developer- and researcher-made measures. https://robertslavinsblog.wordpress.com/2019/10/24/developer-and-researcher-made-measures/ Snow, C. E., & Matthews, T. J. (2016). Reading and language in the early grades. The Future of Children, 26(2), 57-74. Steiner, P. M., Wong, V. C., & Anglin, K. (2019). A causal replication framework for designing and assessing replication efforts. Zeitschrift für Psychologie, 227(4), 280–292. https://doi.org/10.1027/2151-2604/a000385 Prepublication Copy, Uncorrected Proofs 

EVIDENCE ON THE EFFECTIVENESS OF PRESCHOOL CURRICULA 2-14 Valentino, R. (2018). Will public pre-K really close achievement gaps? Gaps in prekindergarten quality between students and across states. American Educational Research Journal, 55(1), 79-116. https://doi.org/10.3102/0002831217732000 Wakabayashi, T., Andrade-Adaniya, F., Schweinhart, L. J., Xiang, Z., Marshall, B. A., & Markley, C. A. (2020). The impact of a supplementary preschool mathematics curriculum on children's early mathematics learning. Early Childhood Research Quarterly, 53, 329-342. https://doi.org/10.1016/j.ecresq.2020.04.002 Watts, T. W., Duncan, G. J., Clements, D. H., & Sarama, J. (2018). What is the long‐run impact of learning mathematics during preschool? Child Development, 89, 539-555. https://doi.org/10.1111/cdev.12713 Weiland, C. (2018). Pivoting to the “how”: Moving preschool policy, practice, and research forward. Early Childhood Research Quarterly, 45, 188-192. https://doi.org/10.1016/j.ecresq.2018.02.017 Weiland, C., & Guerrero-Rosada, P. (2022). Widely Used Measures of Pre-K Classroom Quality: What We Know, Gaps in the Field, and Promising New Directions. Measures for Early Success. MDRC. https://www.mdrc.org/publication/widely-used-measures-pre-k-classroom-quality Weiland, C., Barata, M. C., & Yoshikawa, H. (2014). The co‐occurring development of executive function skills and receptive vocabulary in preschool‐aged children: A look at the direction of the developmental pathways. Infant and Child Development, 23(1), 4-21. Weiland, C., McCormick, M., Duer, J., Friedman-Krauss, A., Pralica, M., Xia, S., Nores, M. & Mattera, S. (2022). Mixed-delivery public prekindergarten: Differences in demographics, quality, and children’s gains in community-based versus public school programs across five large-scale systems. EdWorkingPaper: 22-651. Providence, RI: Annenberg Institute at Brown University. https://doi.org/10.26300/pncz-2233 Weiland, C. & Yoshikawa, H. (2012). The effects of large-scale economic change and policies on children’s developmental contexts and developmental outcomes. Child Development Perspectives, 6, 342-350. https://doi.org/10.1111/j.1750-8606.2011.00222.x Weiland, C. & Yoshikawa, H. (2013). Impacts of a prekindergarten program on children’s mathematics, language, literacy, executive function, and emotional skills. Child Development, 84, 2112-2130. https://doi.org/10.1111/cdev.12099 Weiland, C., McCormick, M., Mattera, M., Maier, M., & Morris, P. (2018). Preschool curricula and professional development features for getting to high-quality implementation at scale: A comparative review across five trials. AERA Open, 4(1). https://doi.org/10.1177/2332858418757735 Weiss, M. J., Bloom, H. S., & Brock, T. (2014). A conceptual framework for studying the sources of variation in program effects. Journal of Policy Analysis and Management, 33(3), 778-808. https://doi.org/10.1002/pam.21760 Wilson, S. J., Dickinson, D.K., & Rowe, D.W. (2013). Impact of an Early Reading First program on the language and literacy achievement of children from diverse language backgrounds. Early Childhood Research Quarterly, 28(2), 578-592. https://doi.org/10.1016/j.ecresq.2013.03.006 Wong, V. C., Cook, T. D., Barnett, W. S., & Jung, K. (2008). An effectiveness‐based evaluation of five state pre‐kindergarten programs. Journal of Policy Analysis and Management: 27(1), 122-154. https://doi.org/10.1002/pam.20310 Yoshikawa, H., Leyva, D., Snow, C. E., Treviño, E., Rolla, A., Barata, M. C., Weiland, C., & Arbour, M. C. (2015). Experimental impacts on classroom quality of an initiative to improve the quality of preschool education in Chile: A cluster-randomized trial. Developmental Psychology, 51(3), 309-322. https://doi.org/10.1037/a0038785 Yoshikawa, H., Weiland, C., Brooks-Gunn, J., Burchinal, M.R., Espinosa, L.M, Gormley, W.T, Ludwig, J.O., Magnuson, K.A., Phillips, D.A., & Zaslow, M.J. (2013). Investing in our future: The evidence base on preschool education. New York, NY: Foundation for Child Development and Ann Arbor, MI: Society for Research in Child Development. https://www.fcd-us.org/the-evidence-base-on- preschool/ Prepublication Copy, Uncorrected Proofs