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March 2019


What research is available pertaining to the impact of class size on student achievement?


Following an established REL Southeast research protocol, we conducted a search for research reports as well as descriptive study articles on the impact of class size on student achievement. We focused on identifying resources that specifically addressed the impact of class size on student achievement. The sources included ERIC and other federally funded databases and organizations, research institutions, academic research databases, and general Internet search engines (For details, please see the methods section at the end of this memo.)

We have not evaluated the quality of references and the resources provided in this response. We offer them only for your reference. These references are listed in alphabetical order, not necessarily in order of relevance. Also, we searched the references in the response from the most commonly used resources of research, but they are not comprehensive and other relevant references and resources may exist.

Research References

  1. Achilles, C. M. (2012). Class-size policy: The STAR experiment and related class-size studies. NCPEA Policy Brief, 1(2), 1-9.
    From the abstract: "This brief summarizes findings on class size from over 25 years of work on the Tennessee Student Teacher Achievement Ratio (STAR) randomized, longitudinal experiment, and other Class-Size Reduction (CSR) studies throughout the United States, Australia, Hong Kong, Sweden, Great Britain, and elsewhere. The brief concludes with recommendations. The STAR research shows that small classes (15-17 pupils) in kindergarten through third grade (K-3) provide short- and long-term benefits for students, teachers, and society at large. Although all students benefit; poor, minority, and male students reap extra benefits in terms of improved test outcomes, school engagement, and reduced grade retention and dropout rates. Differing formulas for counting students and teachers are a major impediment to understanding and using small classes correctly: a pupil-teacher ratio (PTR) is a division problem, class size is an addition problem. The two are not the same, and thus PTR data cannot be used as a substitute for actual class-size data."
  2. Blatchford, P., Bassett, P., & Brown, P. (2011). Examining the effect of class size on classroom engagement and teacher-pupil interaction: Differences in relation to pupil prior attainment and primary vs. secondary schools. Learning and Instruction, 21(6), 715-730.
    From the abstract: "It is widely recognized that we need to know more about effects of class size on classroom interactions and pupil behavior. This paper extends research by comparing effects on pupil classroom engagement and teacher-pupil interaction, and examining if effects vary by pupil attainment level and between primary and secondary schools. Systematic observations were carried out on 686 pupils in 49 schools. Multilevel regression methods were used to examine relationships between class size and observation measures, controlling for potentially confounding factors like pupil attainment. At primary and secondary levels smaller classes led to pupils receiving more individual attention from teachers, and having more active interactions with them. Classroom engagement decreased in larger classes, but, contrary to expectation, this was particularly marked for lower attaining pupils at secondary level. Low attaining pupils can therefore benefit from smaller classes at secondary level in terms of more individual attention and facilitating engagement in learning. (Contains 4 tables and 7 figures.)"
  3. Blatchford, P., Russell, A., Bassett, P., Brown, P., & Martin, C., (2007). The effect of class size on the teaching of pupils aged 7-11 years. School Effectiveness and School Improvement, 18(2), 147-172.
    From the abstract: "There is still little consensus on whether and how teaching is affected by small and large classes, especially in the case of students in the later primary years. This study investigated effects of class size on teaching of pupils aged 7-11 years. We used a multimethod approach, integrating qualitative information from teachers' end-of-year accounts and data from case studies with quantitative information from systematic observations. Results showed that there was more individual attention in smaller classes, a more active role for pupils, and beneficial effects on the quality of teaching. It is suggested that teachers in both large and small classes need to develop strategies for more individual attention but also recognize the benefits of other forms of learning, for example, group work. (Contains 1 table.)"
  4. Bosworth, R. (2014). Class size, class composition, and the distribution of student achievement. Education Economics, 22(2), 141-165.
    From the abstract: "Using richly detailed data on fourth and fifth grade students in the North Carolina public school system, the author finds evidence that students are assigned to classrooms in a non-random manner. Moreover, this non-random assignment is statistically related to class size for a number of student characteristics and that failure to control for classroom composition can severely bias traditionally estimated class size effects. Students who struggle in school appear to benefit more from class size reductions than students in the top of the achievement distribution. Smaller classes have smaller achievement gaps on average and that class size reductions may be relatively more effective at closing achievement gaps than raising average achievement; however, class size effects on both average achievement and achievement gaps are small."
  5. Bowne, J. B., Magnuson, K. A., Schindler, H. S., Duncan, G. J., & Yoshikawa, H. (2017). A meta-analysis of class sizes and ratios in early childhood education programs: are thresholds of quality associated with greater impacts on cognitive, achievement, and socioemotional outcomes? Educational Evaluation and Policy Analysis, 39(3), 407-428.
    From the abstract: "This study uses data from a comprehensive database of U.S. early childhood education program evaluations published between 1960 and 2007 to evaluate the relationship between class size, child-teacher ratio, and program effect sizes for cognitive, achievement, and socioemotional outcomes. Both class size and child-teacher ratio showed nonlinear relationships with cognitive and achievement effect sizes. For child-teacher ratios 7.5:1 and lower, the reduction of this ratio by one child per teacher predicted an effect size of 0.22 standard deviations greater. For class sizes 15 and smaller, one child fewer predicted an effect size of 0.10 standard deviations larger. No discernible relationship was found for larger class sizes and child--teacher ratios. Results were less clear for socioemotional outcomes due to a small sample."
  6. Chingos, M. M. (2012). The impact of a universal class-size reduction policy: Evidence from Florida's statewide mandate. Economics of Education Review, 31(5), 543-562.
    From the abstract: "Class-size reduction (CSR) mandates presuppose that resources provided to reduce class size will have a larger impact on student outcomes than resources that districts can spend as they see fit. I estimate the impact of Florida's statewide CSR policy by comparing the deviations from prior achievement trends in districts that were required to reduce class size to deviations from prior trends in districts that received equivalent resources but were not required to reduce class size. I use the same comparative interrupted time series design to compare schools that were differentially affected by the policy (in terms of whether they had to reduce class size) but that did not receive equal additional resources. The results from both the district- and school-level analyses indicate that mandated CSR in Florida had little, if any, effect on student achievement."
  7. Chingos, M. M. (2013). Class size and student outcomes: Research and policy implications. Journal of Policy Analysis and Management, 32(2), 411-438.
    From the abstract: "Schools across the United States are facing budgetary pressures on a scale not seen in generations. Times of fiscal exigency force policymakers and education practitioners to pay more attention to the return on various categories of public investment in education. The sizes of the classes in which students are educated are often a focus of these discussions because they are a key determinant of educational spending. The declines in funding currently faced by many schools mean that cuts must be made, but it is often unclear how to make cuts in ways that minimize harm to students. This article reviews the evidence base available to inform such policy decisions. It divides the review of the high-quality evidence on class size into three sections. First, it discusses the Tennessee STAR experiment, which is the most important and influential study because it is the only modern randomized experiment conducted at a significant scale. Second, it reviews the quasi-experimental evidence based on naturally occurring variation in class size that is credibly exogenous to student achievement. Finally, it reviews the quasi-experimental evaluations of two statewide class-size reduction policies. These studies are examined separately because in addition to offering evidence about class size, they also raise important issues related to the design and implementation of class-size policies. (Contains 2 figures, 1 table, and 24 footnotes.)"
  8. Chingos, M. M. (2011). The false promise of class-size reduction. Washington, DC: Center for American Progress.
    From the abstract: "Class-size reduction, or CSR, is enormously popular with parents, teachers, and the public in general. Many parents believe that their children will benefit from more individualized attention in a smaller class and many teachers find smaller classes easier to manage. The pupil-teacher ratio is an easy statistic for the public to monitor as a measure of educational quality, especially before test-score data became widely available in the last decade. Policymakers across the nation, including those in at least 24 states, have taken these ideas to heart and enacted CSR initiatives at costs upward of billions of dollars. These policies, coupled with trends in local school districts, have produced a widespread reduction in the number of students per teacher over the past four decades. Parents, teachers, and policymakers have all embraced CSR as a strategy to improve the quality of public education. There is surprisingly little high-quality research, however, on the effects of class size on student achievement in the United States. The credible evidence that does exist is not consistent, and there are many low-quality studies with results all over the map. The evidence on class size indicates that smaller classes can, in some circumstances, improve student achievement if implemented in a focused way. But CSR policies generally take exactly the opposite approach by pursuing across-the-board reductions in class size at the state or federal level. These large-scale, untargeted policies are also extremely expensive and represent wasted opportunities to make smarter educational investments. The fact that across-the-board CSR policies at the state or district level are not cost-effective does not mean that smaller classes should never be used, but rather that they should be reserved for use in special cases by individual schools. (Contains 1 figure and 38 endnotes.)"
  9. Cho, H., Glewwe, P., & Whitler, M. (2012). Do reductions in class size raise students' test scores? Evidence from population variation in Minnesota's elementary schools. Economics of Education Review, 31(3), 77-95.
    From the abstract: "Many U.S. states and cities spend substantial funds to reduce class size, especially in elementary (primary) school. Estimating the impact of class size on learning is complicated, since children in small and large classes differ in many observed and unobserved ways. This paper uses a method of Hoxby (2000) to assess the impact of class size on the test scores of grade 3 and 5 students in Minnesota. The method exploits random variation in class size due to random variation in births in school and district catchment areas. The results show that reducing class size increases mathematics and reading test scores in Minnesota. Yet these impacts are very small; a decrease of ten students would increase test scores by only 0.04-0.05 standard deviations (of the distribution of test scores). Thus class size reductions are unlikely to lead to sizeable increases in student learning. (Contains 2 figures and 13 tables.)"
  10. Dee, T. S., & West, M. R. (2011). The non-cognitive returns to class size. Educational Evaluation and Policy Analysis, 33(1), 23-46.
    From the abstract: "The authors use nationally representative survey data and a research design that relies on contemporaneous within-student and within-teacher comparisons across two academic subjects to estimate how class size affects certain non-cognitive skills in middle school. Their results indicate that smaller eighth-grade classes are associated with improvements in several measures of school engagement, with effect sizes ranging from 0.05 to 0.09 and smaller effects persisting 2 years later. Patterns of selection on observed traits and falsification exercises suggest that these results accurately identify (or possibly understate) the causal effects of smaller classes. Given the estimated earnings impact of these non-cognitive skills, the implied internal rate of return from an eighth-grade class-size reduction is 4.6% overall, but 7.9% in urban schools. (Contains 15 notes, 10 tables, and 2 figures.)"
  11. Jepsen, C., & Rivkin, S. (2009). Class size reduction and student achievement: The potential tradeoff between teacher quality and class size. Journal of Human Resources, 44(1), 223-250.
    From the abstract: "This paper investigates the effects of California's billion-dollar class-size-reduction program on student achievement. It uses year-to-year differences in class size generated by variation in enrollment and the state's class-size-reduction program to identify both the direct effects of smaller classes and related changes in teacher quality. Although the results show that smaller classes raised mathematics and reading achievement, they also show that the increase in the share of teachers with neither prior experience nor full certification dampened the benefits of smaller classes, particularly in schools with high shares of economically disadvantaged, minority students. (Contains 10 tables, 2 figures and 23 footnotes.)"
  12. Konstantopoulos, S. (2008). Do small classes reduce the achievement gap between low and high achievers? Evidence from Project STAR. Elementary School Journal, 108(4), 275-291.
    From the abstract: "Given that previous findings on the social distribution of the effects of small classes have been mixed and inconclusive, in the present study I attempted to shed light on the mechanism through which small classes affect the achievement of low- and high-achieving students. I used data from a 4-year, large-scale, randomized experiment (project STAR) to examine the effects of small classes on the achievement gap. The sample consisted of nearly 11,000 elementary school students who participated in the experiment from kindergarten to grade 3. Meta-analysis and quantile regression methods were employed to examine the effects of small classes on the achievement gap in mathematics and reading SAT scores. The results consistently indicated that higher-achieving students benefited more from being in small classes in early grades than other students. The findings also indicated that, although all types of students benefited from being in small classes, reductions in class size did not reduce the achievement gap between low and high achievers. (Contains 6 tables.)."
  13. Konstantopoulos, S., & Chung, V. (2009). What are the long-term effects of small classes on the achievement gap? Evidence from the Lasting Benefits Study. American Journal of Education, 116, 125-154.
    From the abstract: "The findings on the social distribution of the immediate and lasting benefits of small classes have been mixed. We used data from Project STAR and the Lasting Benefits Study to examine the long-term effects of small classes on the achievement gap in mathematics, reading, and science scores (Stanford Achievement Test). The results consistently indicated that all types of students benefit more in later grades from being in small classes in early grades. These positive effects are significant through grade 8. Longer periods in small classes produced higher increases in achievement in later grades for all types of students. For certain grades, in reading and science, low achievers seem to benefit more from being in small classes for longer periods. It appears that the lasting benefits of the cumulative effects of small classes may reduce the achievement gap in reading and science in some of the later grades."
  14. Li, W., & Konstantopoulos, S. (2017). Does class-size reduction close the achievement gap? Evidence from TIMSS 2011. School Effectiveness and School Improvement, 28(2), 292-313.
    From the abstract: "Policies about reducing class size have been implemented in the US and Europe in the past decades. Only a few studies have discussed the effects of class size at different levels of student achievement, and their findings have been mixed. We employ quantile regression analysis, coupled with instrumental variables, to examine the causal effects of class size on 4th-grade mathematics achievement at various quantiles. We use data from 14 European countries from the 2011 sample of the Trends in International Mathematics and Science Study (TIMSS). Overall, there are no systematic patterns of class-size effects across quantiles. Class-size effects are generally non-significant and uniform at different achievement levels, which suggests that in most European countries class-size reduction does not have an impact on student achievement and does not close the achievement gap. However, combined estimates across countries indicate that high achievers may benefit more from class-size reduction."
  15. Milesi, C., & Gamoran, A. (2006). Effects of class size and instruction on kindergarten achievement. Educational Evaluation and Policy Analysis, 28(4), 287-313.
    From the abstract: "Although experimental results indicate that smaller classes promote higher achievement in early elementary school, the broader literature on class-size effects is inconclusive. This seeming contradiction raises questions about the generalizability of experimental evidence, an issue that this article addresses by examining the effects of class size on achievement in kindergarten with data from a nationwide survey, the Early Childhood Longitudinal Study-Kindergarten Class of 1998-99. To distinguish class-level from individual-level effects, this analysis utilizes hierarchical linear models. In response to concerns about selectivity, teacher fixed-effects models are also estimated. In an effort to understand the inconsistent findings of the past, the authors examine classroom conditions that may affect the link between class size and academic achievement, and also consider whether class size has different effects for different groups of students. The authors find no evidence of class-size effects on student achievement in either reading or mathematics, and results indicate that class size is equally insignificant for students from different race/ethnic, economic, and academic backgrounds. Teacher fixed-effects analyses also yield null findings for class size. Instructional activities offer significant boosts to achievement, but the effects of instruction do not differ between small and large classes. The authors discuss why the small class size advantage evidenced by experimental research might not generalize to nonexperimental, naturally occurring settings throughout the nation. (Contains 6 tables and 15 notes.)"
  16. Millsap, M. A., Giancola J., Smith, W. C., Hunt, D., Humphrey, D., Wechsler, M., & Riehl, L. (2004). A descriptive evaluation of the federal class-size reduction program: Final report. Washington, DC: U.S. Department of Education, Office of the Deputy Secretary, Policy and Program Studies Service.
    From the abstract: "The federal Class-Size Reduction (CSR) Program, P.L. 105-277, begun in Fiscal Year 1999, represented a major federal commitment to help school districts hire additional qualified teachers, especially in the early elementary grades, so children would learn in smaller classes. The CSR program also allowed funds to be spent as professional development, in part to help teachers take advantage of instructional opportunities in smaller classes. The ultimate goal of the program was to improve student achievement, particularly in reading, by reducing class sizes in grades K-3 to an average of 18 students per class. As part of the reauthorization of the Elementary and Secondary Education Act of 1965 (ESEA), the CSR program was folded into Title II, Part A, of the No Child Left Behind Act of 2001 (NCLB). Although no longer a separate federal program, class-size reduction remains an allowable use of funds under Title II, Part A. It is one of many ways that districts can use their Title II, Part A, funds to improve teacher quality and student achievement in their schools. Therefore, this evaluation provides valuable lessons not just about the federal CSR program, but also about a major component of Title II, Part A, of NCLB. This evaluation was designed to address multiple research questions, organized into three main categories: (1) distribution and uses of federal CSR funds; (2) implementation of CSR; (3) and effects of CSR on class size. This report's structure reflects the four sets of evaluation questions. Chapter 2 addresses the distribution and uses of funds. Chapter 3 addresses recruitment and hiring of teachers, professional development, and resources for implementation. Last, Chapter 4 examines the impact of the federal CSR program on class size. Appended are: (1) Survey of District Personnel; and (2) Survey of School Principals. (Contains 33 tables and 25 footnotes.)"
  17. Shin, Y. (2012). Do black children benefit more from small classes? multivariate instrumental variable estimators with ignorable missing data. Journal of Educational and Behavioral Statistics, 37(4), 543-574.
    From the abstract: "Does reduced class size cause higher academic achievement for both Black and other students in reading, mathematics, listening, and word recognition skills? Do Black students benefit more than other students from reduced class size? Does the magnitude of the minority advantages vary significantly across schools? This article addresses the causal questions via analysis of experimental data from Tennessee's Student/Teacher Achievement Ratio study where students and teachers are randomly assigned to small or regular class type. Causal inference is based on a three-level multivariate simultaneous equation model (SM) where the class type as an instrumental variable (IV) and class size as an endogenous regressor interact with a Black student indicator. The randomized IV causes class size to vary which, by hypothesis, influences academic achievement overall and moderates a disparity in academic achievement between Black and other students. Within each subpopulation characterized by the ethnicity, the effect of reduced class size on academic achievement is the average causal effect. The difference in the average causal effects between the race ethnic groups yields the causal disparity in academic achievement. The SM efficiently handles ignorable missing data with a general missing pattern and is estimated by maximum likelihood. This approach extends Rubin's causal model to a three-level SM with cross-level causal interaction effects, requiring intact schools and no interference between classrooms as a modified Stable Unit Treatment Value Assumption. The results show that, for Black students, reduced class size causes higher academic achievement in the four domains each year from kindergarten to third grade, while for other students, it improves the four outcomes except for first-grade listening in kindergarten and first grade only. Evidence shows that Black students benefit more than others from reduced class size in first-, second-, and third-grade academic achievement. This article does not find evidence that the causal minority disparities are heterogeneous across schools in any given year. (Contains 3 figures, 4 tables, and 1 note.)"
  18. Shin, Y. & Raudenbush, S. W. (2011). The causal effect of class size on academic achievement: Multivariate instrumental variable estimators with data missing at random. Journal of Educational and Behavioral Statistics, 36(2), 154-185.
    From the abstract: "This article addresses three questions: Does reduced class size cause higher academic achievement in reading, mathematics, listening, and word recognition skills? If it does, how large are these effects? Does the magnitude of such effects vary significantly across schools? The authors analyze data from Tennessee's Student/Teacher Achievement Ratio study (STAR) of 1985, where students and teachers are randomly assigned to a small or regular class. The authors propose a three-level multivariate simultaneous equation model with an instrumental variable (IV) and estimation via maximum likelihood (ML) to analyze the data under an assumption of data missing at random (MAR). The IV, random assignment of students to a small or regular class, reduces class size which, by hypothesis, improves academic achievement in these domains. The authors extend Rubin's Causal Model (RCM) by involving a modified Stable Unit Treatment Value Assumption (SUTVA), requiring no interference between classrooms and intact schools. The method accommodates data with a general missing pattern and extracts full information for analysis from the STAR data. The authors investigate both homogenous and heterogeneous causal effects of class size on academic achievement scores across schools. The results show that reducing class size improves reading, mathematics, listening, and word recognition test scores from kindergarten to third grade, although the effects appear relatively small in second grade. The authors find no evidence that the causal effects vary across schools. (Contains 2 figures and 6 tables.)"
  19. Watson, K., Handal, B., & Maher, M. (2016). The influence of class size upon numeracy and literacy performance. Quality Assurance in Education: An International Perspective, 24(4), 507-527.
    From the abstract: "Purpose: The purpose of this paper was to investigate the influences of calendar year, year level, gender and language background other than English (LBOTE) on student achievement in literacy and numeracy relative to class size. Design/methodology/approach: Data for this study were collected over five years (2008-2012) as test results from the Australian National Assessment Plan in Literacy and Numeracy (NAPLAN) in Years 3 and 5 from over 100 Sydney primary schools. Findings: It was found that the most important factors influencing academic performance in literacy and numeracy were, in descending order: gender, LBOTE, the calendar year in which the test was conducted, followed by class size. All variables were significantly associated with NAPLAN performance, but effect size estimates for class size were close to zero. Originality/value: The results of this study support other studies suggesting that factors other than class size are more important in influencing academic performance."
  20. Watts, R. S., & Georgiou, A. (2008). A study on the effects of smaller class size on student achievement. ERS Spectrum, 26(4), 21-30.
    From the abstract: "Since the passage of No Child Left Behind, schools have been looking for resources that are proven, through research, to improve student achievement. The purpose of this article is to determine if there is a relationship between class size and student achievement among 137 school systems in Tennessee. The authors provide a review of the literature on student achievement, including studies on the Student/Teacher Achievement Ratio (STAR) and the National Child Development Study (NCDS). Using a hierarchical regression analysis, the authors examined four achievement measures, controlling for the influence of socioeconomic background. The authors conclude that economic background has a greater influence on academic achievement of elementary school students in Tennessee than high school students; and that after controlling for socioeconomic status, the student-teacher ratio was not significantly related to the four achievement measures. (Contains 6 tables.)"
  21. Whitehurst, G. J., & Chingos, M. M. (2011). Class size: What research says and what it means for state policy. Washington, DC: The Brookings Institute.
    From the abstract: "Class size is one of the small number of variables in American K-12 education that are both thought to influence student learning and are subject to legislative action. Legislative mandates on maximum class size have been very popular at the state level. In recent decades, at least 24 states have mandated or incentivized class-size reduction (CSR). The current fiscal environment has forced states and districts to rethink their CSR policies given the high cost of maintaining small classes. The substantial expenditures required to sustain smaller classes are justified by the belief that smaller classes increase student learning. The authors examine "what the research says" about whether class-size reduction has a positive impact on student learning and, if it does, by how much, for whom, and under what circumstances. Despite there being a large literature on class-size effects on academic achievement, only a few studies are of high enough quality and sufficiently relevant to be given credence as a basis for legislative action. (Contains 31 footnotes.)"
  22. Wyss, V. L., Tai, R. H., & Sadler, P. M. (2007). High school class-size and college performance in science. The High School Journal, 90, 45-53.
    From the abstract: "This paper focuses on the influence of high school science class size on students' achievement in introductory college science courses and on the variation of teacher practice across class size. Surveys collected information about high school science class experiences from 2754 biology, 3521 chemistry, and 1903 physics students across 36 public and 19 private institutions from 31 different states. The first analysis includes a cross-tabulation of 6 different class sizes and the frequencies of teacher practices reported by students. The second analysis includes a multiple linear regression of class size and student achievement. Results show no differences for pedagogy and student achievement until class sizes fall to 10 or fewer students. These findings suggest that incremental reductions in class size are likely not to have a significant impact on later student achievement. (Contains 1 figure, 1 table, and 5 footnotes.)"

Additional Organizations to Consult

Center for Public Education:
From the website: "The Center for Public Education (Center) is a national resource for accurate, timely, and credible information about public education and its importance to the well-being of our nation. The Center provides up-to-date research, data, and analysis on current education issues and explores ways to improve student achievement and engage public support for public schools. Our intended audience includes school board members and other policymakers, educators, community leaders, parents, and everyone concerned with the education of our children. The Center is an initiative of the National School Boards Association (NSBA)."


Keywords and Search Strings
The following keywords and search strings were used to search the reference databases and other sources:

  • Class size and student achievement
  • Class size
  • Effect of class size on student achievement
  • Impact of class size on student achievement

Databases and Resources
We searched ERIC for relevant resources. ERIC is a free online library of over 1.6 million citations of education research sponsored by the Institute of Education Sciences. Additionally, we searched Google Scholar and PsychInfo.

Reference Search and Selection Criteria

When we were searching and reviewing resources, we considered the following criteria:

  • Date of the publication: References and resources published for last 15 years, from 2003 to present, were include in the search and review.
  • Search Priorities of Reference Sources: Search priority is given to study reports, briefs, and other documents that are published and/or reviewed by IES and other federal or federally funded organizations, academic databases, including ERIC, EBSCO databases, JSTOR database, PsychInfo, PsychArticle, and Google Scholar.
  • Methodology: Following methodological priorities/considerations were given in the review and selection of the references: (a) study types - randomized control trials,, quasi experiments, surveys, descriptive data analyses, literature reviews, policy briefs, etc., generally in this order (b) target population, samples (representativeness of the target population, sample size, volunteered or randomly selected, etc.), study duration, etc. (c) limitations, generalizability of the findings and conclusions, etc.

This memorandum is one in a series of quick-turnaround responses to specific questions posed by educational stakeholders in the Southeast Region (Alabama, Florida, Georgia, Mississippi, North Carolina, and South Carolina), which is served by the Regional Educational Laboratory Southeast at Florida State University. This memorandum was prepared by REL Southeast under a contract with the U.S. Department of Education's Institute of Education Sciences (IES), Contract ED-IES-17-C-0011, administered by Florida State University. Its content does not necessarily reflect the views or policies of IES or the U.S. Department of Education nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.