• Key Findings of the ECLS-K Report
• Concluding Remarks
• References

ECLS-K began in the fall of 1998 with a nationally representative sample of approximately 23,000 U.S. kindergarten students. These students were assessed in fall 1998, spring 1999, fall 1999, and spring 2000, in math, reading, and general knowledge; and in spring 2002, in math, reading, and science. Their parents, teachers, and principals were also surveyed. Most recently, the ECLS-K assessment was conducted in spring 2004, when most students were in the fifth grade. This current report summarizes patterns of children's achievement in math, reading, and science-and patterns of children's interest in school, sense of academic competence, and problem behaviors-in third grade.

ECLS-K is one of a long line of longitudinal studies conducted by NCES to examine the associations among schooling policies and practices, family background and environment, individual characteristics, and educational and social outcomes (including educational achievement, educational attainment, and labor force outcomes). Most of these studies, however, have followed adolescent and young adult cohorts, beginning in middle school, high school, or college, and so have provided no evidence on educational patterns and processes in the early childhood and elementary school years.¹ ECLS-K is the first nationally representative longitudinal study focused on schooling processes and outcomes to begin with a cohort as young as kindergarten age. As such, it provides a rich source of data unmatched in any other extant dataset.

If the early childhood years-particularly those that correspond with the early elementary grades-are crucial in shaping young children's academic identities and skills, then it is essential that educators, policymakers, and researchers have access to reliable evidence about the educational and social factors that promote early reading and math skills, positive academic self-concepts, and strong social skills in the elementary school years. Moreover, the ability of ECLS-K to link students' achievement trajectories to a rich set of variables describing their educational contexts and experiences provides potentially valuable evidence for educators and policymakers regarding how best to structure schooling.

Probably the single most useful aspect of ECLS-K is that it provides detailed, high-quality longitudinal achievement data for a nationally representative sample of elementary school students. These data enable researchers to examine, in detail, students' trajectories of cognitive development in math and reading. At present, available ECLS-K data span the first 4 years of schooling (K-3), although fifth-grade data have already been collected and are scheduled for release within the next year. Plans are being made to follow the sample through middle and high school, holding out the possibility that ECLS-K will be the first nationally representative dataset to contain longitudinal data from kindergarten through 12th grade.

The availability of longitudinal achievement data for kindergarten through third grade yields powerful descriptive evidence about the development of cognitive skills during early elementary school. Variations in the rates at which children acquire different literacy and math skills allow us to observe both the development and/or narrowing of achievement gaps among demographic subgroups and the association of achievement trajectories with education policies and practices.

Racial/ethnic achievement gaps

One of the key findings of the ECLS-K report is that racial/ethnic gaps in math and reading skills-which prior reports have shown to be large at the start of kindergarten (Fryer and Levitt 2004; West, Denton, and Reaney 2001)-remain large through third grade. In particular, Black students, who start kindergarten with average math and reading scores well below those of White, non-Hispanic students, make smaller gains in math and reading between kindergarten and third grade than do White, Hispanic, and Asian/Pacific Islander students.

Some, but not all, of the Black-White gap in third grade can be attributed to racial differences in family socioeconomic status. Prior research using ECLS-K data has shown that the Black-White gap in math and reading at the start of kindergarten can be attributed entirely to racial differences in family socioeconomic status (Fryer and Levitt 2004; Reardon 2003); this is no longer true, however, by third grade (Fryer and Levitt 2005). Black children have, on average, lower math and reading scores in third grade than do White children from similar socioeconomic backgrounds. This finding-that the Black-White achievement gap between socioeconomically similar children is null at kindergarten entry but sizable² by third grade-suggests that schooling plays some role in producing the achievement gap.

The Black-White achievement gap has received considerable attention in the last decade (e.g., Jencks and Phillips 1998), but comparably less research has been done to understand the achievement trajectories of minority groups other than Blacks. One of the strengths of ECLS-K is its relatively large samples of Hispanic and Asian students. The ECLS-K report shows that Hispanic students' average math, reading, and science scores fall roughly midway between those of White and Black students, while Asian students, on average, have achievement levels similar to those of White students. There is, however, considerable heterogeneity in both Hispanic and Asian students' achievement trajectories, some of which is related to differences in, for example, English proficiency, country of origin, and immigrant generation (Galindo and Reardon 2004). Given the growth of the immigrant population in the United States, a better understanding of the factors that contribute to educational success for Hispanic, Asian, and other immigrant groups is essential. No nationally representative longitudinal dataset other than ECLS-K includes such large samples of immigrant students.

School mobility

Another important topic addressed in the report is school mobility. The report indicates that 49 percent of 1998–99 first-time kindergarteners had changed schools at least once by the spring of third grade; 10 percent had changed schools two or more times in the first 4 years of schooling. Students change schools in the elementary grades for a variety of reasons, including family residential moves, school district policies (some districts have separate kindergarten and elementary grade schools, so all students must change schools at the start of kindergarten), and moves between the public and private schooling sectors. Moreover, some students change schools between grades, while others change schools during the school year. Midyear school transitions associated with residential moves-particularly residential moves due to family income instability-are likely to have the most detrimental effect on children's achievement trajectories. While the report does not examine these issues, the substantial school mobility it documents suggests the need for a better understanding of the associations among residential mobility, school mobility, and education outcomes.

Achievement differences between public and private schools

The report also addresses the association between patterns of achievement and public/private school enrollment. It calls attention to the finding that students enrolled in private schools from kindergarten through third grade have, on average, higher levels of literacy and math skills than students enrolled in public schools. This finding is accurate, but should not be taken to imply that private schools have a causal effect on learning, since, as the report notes in its conclusion, private school students also have higher average achievement scores when they enter kindergarten and show gains equal to those of public school students during the period from kindergarten through third grade (West, Denton, and Reaney 2001). Thus, it is likely that most, if not all, of the public/private school differences in third-grade achievement are attributable to differences in skill levels between the populations of students entering schools in each sector, rather than to differences in the average quality of public and private schools.

Student perceptions about school

Finally, the report describes patterns of student responses to the ECLS-K self-description questionnaire (SDQ). The SDQ was administered to ECLS-K students for the first time in third grade, and measured students' perceptions about their academic competence, peer relations, and problem behaviors. Perhaps the most notable finding in this section of the report is that there are very few significant differences in students' perceptions of their competence by race or family background; in general, most students report generally positive interest and competence in school. This suggests that any racial differences in motivation and academic self-concept that are observed in high school must arise after the early elementary grades. Subsequent waves of data from ECLS-K may shed light on the evolution of academic self-concept and attitudes toward schooling through the later elementary grades and middle school.

Although there are few substantial group differences in self-reported academic interest or competence in third grade, the SDQ does reveal significant differences in peer relationships and problem behaviors by race. Black students reported substantially higher levels of both internalizing and externalizing problem behaviors than did White students. More investigation of these patterns is certainly warranted, as they may have deleterious effects on students' subsequent achievement.

In order to provide policymakers, educators, and the public with the most useful education policy analyses, education researchers should provide both (1) careful descriptive analyses of educational environments, experiences, and outcomes (think of this as "educational epidemiology," a tool that enables researchers and policymakers to focus attention where the least is known and the most intervention is needed); and (2) research and evaluation methods that enable us to make strong causal inferences about the impacts of education practices and policies.

One of the strengths of longitudinal observational education studies such as ECLS-K is that they provide a detailed descriptive picture of the achievement trajectories and educational experiences of a nationally representative sample of a specific cohort of students. As education is a developmental enterprise, detailed longitudinal descriptive analyses of achievement trajectories and the development of academic and social behaviors are an essential part of any useful "educational epidemiology."

The corresponding drawback of studies such as ECLS-K is that they do not readily enable researchers and policymakers to draw strong causal inferences about the effects of specific education practices and policies. The finding that students enrolled in private schools have higher achievement scores than students enrolled in public schools, for example, likely reflects simply the selection of students from more advantaged backgrounds into private schools rather than a causal effect of private schooling on achievement. That "correlation does not imply causality" must be taken seriously in all analyses of studies such as ECLS-K.

That said, it is possible to learn something about the effects of schooling practices and policies on achievement (or other schooling outcomes) by analyzing the data from longitudinal observational studies such as ECLS-K. Researchers might take advantage of natural experiments evident in the data, or use instrumental variables; matching estimators; regression discontinuity; school-, classroom-, and student-fixed effects; difference-in-difference estimators; or other econometric techniques to identify some plausibly exogenous variations in classroom, school, district, or state education practices and policies. In the absence of randomized experiments (which are often infeasible or unethical in many areas of education research), researchers can-and should-use ECLS-K and other large longitudinal observational datasets to provide whatever strong evidence can be gleaned regarding the effects of education practices and policies. This, in combination with detailed descriptive analyses of the sort provided in From Kindergarten Through Third Grade, will help ensure that our education practices develop in line with our best knowledge of effective practices.

Fryer, R.G., and Levitt, S.D. (2004). Understanding the Black-White Test Score Gap in the First Two Years of School. The Review of Economics and Statistics, 86(2): 447-464.

Fryer, R.G., and Levitt, S.D. (2005). The Black-White Test Score Gap Through Third Grade. Cambridge, MA: National Bureau of Economic Research.

Galindo, C., and Reardon, S.F. (2004, April). Hispanic Elementary School Students, Immigration, Language and Achievement. Paper presented at the annual meeting of the American Educational Research Association, San Diego, CA.

Jencks, C., and Phillips, M. (Eds.) (1998). The Black-White Test Score Gap. Washington, DC: Brookings Institution Press.

Reardon, S.F. (2003). Sources of Educational Inequality: The Growth of Racial/Ethnic and Socioeconomic Test Score Gaps in Kindergarten and First Grade. University Park, PA: Population Research Institute, Pennsylvania State University.

West, J., Denton, K., and Reaney, L.M. (2001). The Kindergarten Year: Findings from the Early Childhood Longitudinal Study, Kindergarten Class of 1998–99 (NCES 2001-023). U.S. Department of Education, National Center for Education Statistics. Washington, DC: U.S. Government Printing Office.

¹ For example, the High School and Beyond Longitudinal Study (HS&B) followed cohorts of 10th- and 12th-graders for 12 and 6 years, respectively, beginning in 1980; the Nation-al Education Longitudinal Study of 1988 (NELS:88) followed a cohort of 8th-graders for 12 years beginning in 1988; and the Baccalaureate and Beyond Longitudinal Study (B&B) has followed the educational and work experiences of bachelor's degree completers beginning with a cohort of 1992–93 completers.

² Fryer and Levitt (2005) estimate the Black-White gap at third grade in math and reading, net of socioeconomic characteristics, to be approximately .40 standard deviations.