Class Size Reduction in California: Findings from 1999-00 and 2000-01
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Brian M. Stecher and George W. Bohrnstedt

This third report on our ongoing evaluation of California's Class Size Reduction (CSR) program brings us up through the 2000-01 school year. We update our previous findings on the implementation of the CSR program in grades K-3 and on how the program has affected the qualifications of teachers, curriculum and instruction, student achievement, and special populations. In most cases, this report adds two years of data to the findings contained in our second CSR evaluation report (Stecher and Bohrnstedt, 2000). It also provides updated information on how districts and schools have allocated resources in support of CSR, a topic last discussed in our first CSR evaluation report (Bohrnstedt and Stecher, 1999). Our next report, which will be the fourth and final in the series, will be issued in June 2002. It will synthesize all the results of our evaluation, paying particular attention to policy questions related to CSR.

What we found in the third year of our evaluation is that CSR had been essentially fully implemented in grades K-3 by 2000-01, and that there were no longer differences in school/district participation in the program related to student demographic characteristics. For the most part, resources (including facilities and funds) continue to be reallocated away from other programs to support the implementation of CSR, and in most districts, the cost of CSR still exceeded the reimbursement received from the state.

The decline in teacher qualifications that occurred in the program's early years has slowed or stopped. In 2000-01, approximately 85 percent of K-3 teachers were fully credentialed. Similarly, the difference in teacher qualifications between schools serving the most and those serving the fewest low-income students1 leveled off after having grown dramatically during the program's first three years. But the gap in teacher credentialing in low- versus high-income schools persisted. In 2000-01, about 96 percent of K-3 teachers in schools serving the fewest low-income students were fully credentialed, whereas the corresponding figure in schools serving the most low-income students was 79 percent.

Statewide, the average achievement scores of students in all elementary grades have increased annually since the Standardized Testing and Reporting (STAR) testing program began in 1997-98. However, the statewide pattern of score increase in the elementary grades does not match the statewide pattern of exposure to CSR, so no strong relationship can be inferred between achievement and CSR. In addition, California was implementing a number of significant new programs at the same time CSR was being implemented, and it is impossible to attribute changes in achievement scores to any single cause. It also is difficult to say how much of the gain in achievement test scores is real and how much reflects inflation in scores brought about by teachers learning to "teach to" a new test. This kind of inflation is often observed with the introduction of new high stakes test such as the STAR test adopted in California in 1996-97. Finally, CSR does not appear to have affected the rates at which students are identified as needing special education, or the percentage of special education students who are taught in special day classes.


In 1996, the California legislature passed SB 1777, a reform measure aimed at cutting class size in the early school grades from what had been an average of 29 students to a maximum of 202. The program is voluntary; school districts that chose to participate in 2000-01 received about $850 for each K-3 student enrolled in a class of 20 or fewer students. (The per capita amount has risen annually since the program's inception.) The CSR program was inspired by an experiment conducted in Tennessee from 1985 to 1990 known as the Tennessee STAR (Student/Teacher Achievement Ratio) project. This experimental program produced relatively large achievement gains for all students, and the gains for low-income and minority students were almost twice as large as the gains for other students.

However, there are substantial differences between Tennessee's and California's situations. The Tennessee program was a carefully controlled experiment (with random assignment of both teachers and students to small or regular size classes) involving about 10,000 students; the California program has been implemented statewide and serves 1.8 million students. California reduced its maximum class size of 33 students to 20; Tennessee took its class size of 22-26 students down to 13-17. California serves a student population that is decidedly more ethnically and linguistically diverse than Tennessee's. And, California schools lack two important ingredients that Tennessee schools had-adequate space and enough qualified teachers for program implementation. Because of these differences, California's CSR program must be judged on its own terms rather than as a replication of the Tennessee experiment.

In 1997-98, the state of California selected a consortium of organizations-American Institutes for Research (AIR), RAND, Policy Analysis for California Education (PACE), WestEd, and EdSource-to conduct a four-year evaluation of the CSR program. The Consortium released its first report in June 1999; it covered the initial two years of the CSR program. A second report, covering the 1998-99 school year, was issued in June 2000. This third report presents findings for the 1999-00 and 2000-01 school years.


Our evaluation drew upon three major sources of data. In the spring 2000, the Consortium sent surveys to a representative sample of district superintendents, school principals, and classroom teachers in grades 1 through 4. The surveys contained questions about the themes of this evaluation: implementation, resource usage, district and school administration, classroom practices (including curriculum, instruction, and student behavior), and attitudes toward CSR. In addition to this survey data, we used results from California's Standardized Testing and Reporting (STAR) program, the California Basic Educational Data System (CBEDS), and Personnel Assignment Information Form (PAIF)3. The STAR data consisted of Stanford Achievement Test, 9th Edition (SAT-9) test scores along with student background information. The PAIF data included teachers' assignments and information about their educational background and teaching experience. Finally, we obtained state archival data on CSR implementation, expenditures, special education students, and other relevant information.


CSR Implementation Is Essentially Complete

California's CSR reform effort had attained almost full implementation by the 2000-01 school year, the program's fifth year. As Figure 1 shows, at that time 97 percent of the state's K-3 students were enrolled in classes of 20 or fewer, and 99 percent of all eligible districts were participating in the program.

figure 1

Also, for the first time since the program's inception in 1996, implementation rates varied little by grade level or student demographic characteristics. The gap in CSR implementation between districts and schools with low versus high percentages of low-income, minority4, or English learner (EL)5 students that had persisted for the first years of CSR had been all but eliminated.

The Decline in Elementary Teacher Qualifications Has Leveled Off But Remains Substantial

The rapid growth in the K-3 teacher workforce documented in our earlier CSR evaluation reports leveled off by 2000-01, and, for the most part, so did the decline in teacher qualifications (see Figure 2). The percentage of elementary school teachers without full credentials increased rapidly from 1995-96 through 1998-99, but stayed the same or declined slightly in 2000-01. In comparison, the increase in the percentage of secondary school teachers without full credentials during this period was slower and continued through 2000-01. As a result, the problem of under-qualified teachers is almost as great in middle schools as it is in elementary schools, and CSR does not affect the middle school grades.

figure 2

The Gap in K-3 Teacher Qualifications Persists, but Did Not Worsen

In 2000-01, the difference in teacher qualifications between elementary schools that served larger proportions of low-income, minority, or EL students and those that served smaller proportions of low-income, minority, or EL students declined for the first time since 1996-97 when CSR began implementing (see Figure 3). Between 1995-96 and 1997-98, elementary schools that served larger proportions of low-income, minority, or EL students had relatively larger increases in the proportion of K-3 teachers who were not fully credentialed than schools serving smaller proportions of low-income students. The gaps in K-3 teacher qualifications between schools that served different population groups then grew much more slowly between 1997-98 and 1999-00. In 1999-00 and 2000-01, the overall qualifications of California's elementary teachers began to improve slightly, and the gaps in teacher qualifications between schools began to decline slightly but remained strikingly large.

figure 3

Districts and Schools Continued to Reallocate Resources to Support CSR

Resource limitations continue to be a concern for districts as they implement CSR. In fact, one district in southern California recently decided to eliminate CSR in third grade as part of a larger effort to balance its budget for the 2002-03 school year. Almost two-thirds of districts reported that the state reimbursement for CSR is insufficient to cover actual district costs. Overall, the CSR program has required that districts and schools reallocate funds and space away from a variety of support and educational programs, and this reallocation has not lessened over time (see Figure 4). Some of the programs affected are arguably relatively low priority for principals, superintendents, and parents- programs such as administration, music/arts, gym, and sports. However, higher-priority programs, such as professional development, computer labs, libraries, and after school programs, have also been impacted. It remains to be seen how this reallocation of resources may affect students' overall education and performance over the long term. Additional information about district budget constraints and intentions regarding CSR will be available in our fourth year evaluation report.

figure 4

Students in Reduced Size Classes Received More Individual Instruction But Not Different Curriculum or Learning Activities

In all three CSR surveys (1998, 1999, 2000), teachers in reduced size classes reported that they devoted more instructional time to small groups and working with individuals during mathematics and language arts lessons than did teachers in non-reduced size classes. In addition, teachers in smaller classes also provided comparatively more extended attention to poor readers (see Table 1), and they were more positive about their ability to assess and meet student needs and to provide students with quick feedback and individual attention. Reduced class size was related to better-disciplined students on some but not all measures, and in some but not all years.

table 1

However, teachers reported few differences in curriculum regardless of class size. Whether they were teachers in a reduced or a non-reduced class, they covered about the same number of mathematics and language arts topics and devoted about the same amount of time to each major curriculum element in 1998, 1999, and 2000. We also found that there were few differences between reduced and non-reduced classes in terms of language arts or mathematics learning activities.

Achievement Scores Improved But Effect of CSR Remains Uncertain

Because CSR was almost fully implemented by 2000-01, we could not analyze achievement differences between students in reduced and non-reduced size classes as we had in the past. Furthermore, at the time this report was written the only achievement data available for 2000-01 were statewide average scores by grade level. As a result, our analysis was limited to comparisons of achievement among statewide cohorts of students with different average amounts of exposure to CSR. We compared cohorts that entered kindergarten from 1991 to 1998 to see whether patterns of achievement were related to patterns of exposure.

For each cohort we examined, the average SAT-9 scale score increased annually (see Figure 5). More importantly, the average score of each succeeding cohort was higher than that of the previous cohort at a given level. Thus, achievement has been increasing during CSR's implementation.

figure 5

CSR began in 1996-97 with first grade (and other grades in a few cases). In subsequent years, additional grades were added. Successive cohorts of students received more exposure to CSR at each grade level, on average, than did previous cohorts (see Figure 6).

figure 6

To determine whether there was a relationship between CSR exposure and achievement, we compared differences in achievement and differences in CSR exposure between each successive cohort of students in second grade and third grade (see Figure 7). If there were a positive relationship between CSR and achievement, the points on the graph would be clustered in what would look like a line sloping upward from left to right. We would see some points with a small difference in achievement and a small difference in exposure to CSR, and others with a large difference in achievement and a large difference in CSR exposure. However, we did not find such a pattern. There was no strong association between differences in exposure and differences in achievement effects during this period.

figure 7

CSR Has Had Little Effect on Students from Special Populations

The statewide data continued to show that CSR has had little impact on participation in special education. There has been no increase in the percentage of K-3 students identified as needing special education services since CSR was introduced. Furthermore, there has been no increase in the percentage of K-3 students in special education who are placed in special day classes. The CSR program put additional pressure on services for special education students, as we noted in our previous evaluation reports. Many schools reallocated special education facilities, and many teachers switched from teaching special education students to teaching in regular K-3 classes. Similarly, there was little evidence that CSR had a specific effect on EL students. Schools with the largest proportion of EL students had the largest number of teachers specifically credentialed to work with EL students. However, we found that the distribution of such teachers per 100 EL students actually favored schools with fewer EL students.


This interim report should be read as an update on the CSR program for the 1999-00 and 2000-01 school years. Some of the negative effects previously observed had moderated by 2000-01, but others remained. And important differences between schools serving different student population groups persisted. When we looked at student achievement statewide, we did not find a strong association between achievement and CSR participation. In general, we did not attempt to draw summative conclusions about the overall effectiveness of the CSR program in this report, nor did we develop recommendations for policymakers. The fourth and final CSR evaluation report, which will be issued in the June 2002, will synthesize the evidence we have collected over the past four years and will focus on the policy lessons that can be learned. It will also contain additional analyses exploring the relationship between teacher characteristics and student achievement gains in reduced size classes. See Appendix D for a list of topics to be covered in the final report.

1 Students are referred to as low-income or as being from low-income families in this report if state records classify them as receiving public assistance in the form of Aid to Families with Dependent children (AFDC) or its successor in California, CalWORKS.

2 SB 1777 required that a school first reduce the size of its grade 1 classes, then its grade 2 classes. Once its grade 2 classes were reduced, the school could choose to reduce its kindergarten or grade 3 classes.

3 Neither the student nor the teacher files contained individual names or direct identifiers.

4 Minority students are any students not classified as Caucasian. The largest groups of minority students are, in order of group size, Hispanics, Asian/Pacific Islanders, and African Americans.

5 Students for whom English is a second language and who are not fully proficient in English are often referred to as limited English proficient (LEP), English language learners (ELL), and English learners (EL). We use EL throughout this report to reflect the usage in the California law that implemented proposition 227, a proposition passed by California's voters in 1998 that banned the implementation of bilingual education except under special parental waiver conditions.