Frequently Asked Questions About California’s Charter Schools: 2008 Performance Update

June 2008

Study findings Press release

How do California charter schools compare to traditional public schools?

The study reviewed both charter and traditional public school performance on achievement tests at the elementary, middle, and high school levels. It found that, on average, charter middle schools outperformed noncharter middle schools on all measures by substantial margins. Charter elementary schools had lower API scores, on average, than their noncharter peers. However, when nonclassroom-based charters were excluded from the analysis, the difference in API scores was no longer statistically significant.

Charter high schools outperformed traditional public high schools overall, although traditional public schools performed better on standards-based math tests. However, when nonclassroom-based charters were removed from the analysis, charters scored higher than traditional public schools on all measures.

A recent report from the California Charter Schools Association showed that Los Angeles Unified School District (LAUSD) elementary and middle school charters were doing better than traditional public schools. EdSource suggests these schools are not performing significantly better. What explains the difference?

The California Charter Schools Association study did not control for school size and student background. The latter is an especially important factor in evaluating school performance because academic achievement is heavily influenced by the demographic characteristics of the student body. Once these factors were taken into consideration, the difference in achievement for charters and traditional public schools was not statistically significant at the elementary and middle schools levels but was significant at the high school level.

What is the difference between a "classroom-based" charter school and a "nonclassroom-based" charter school?

A classroom-based charter is a school that requires pupils to be on campus and under the direct supervision of a teacher for at least 80 percent of instructional time. Approximately 80 percent of charter schools in California are classroom-based. Nonclassroom-based charter schools, which include independent study programs and home-schooling support networks, do not meet the 80 percent on-campus threshold.

How does this analysis compare to last year's EdSource charter school report?

After comparing charters and traditional public schools once again, the researchers found similar results. Charter middle and high schools had higher API scores than traditional public schools. Charter elementary schools, however, scored lower on the API than their traditional public school counterparts. In addition, math scores were lower in charter elementary and high schools (though other research suggests this may be due to students' math skills when they enter charter schools), and nonclassroom-based charters did not perform as well as classroom-based charters.

New to this year's report:

• EdSource released data for specific districts. This year there is an examination of charter school performance in LAUSD, San Diego Unified School District (SDUSD), and Oakland Unified School District (OUSD).
• The researchers reviewed whether charter schools were meeting state performance standards for charter renewal.

What is a charter school?

A charter school is a public school that operates under a specific performance agreement (charter) approved by a school district, county office of education, or the State Board of Education. Charter schools are subject to fewer restrictions than traditional public schools, but they are accountable for meeting student achievement goals specified in the charter and under state and federal accountability policies.

How many charter schools currently operate in California?

Since the Charter Schools Act was passed in 1992, the number of charter schools has grown steadily. There were 617 charter schools operating in California during the 2006-07 academic year with a combined enrollment of 225,095 students, or 3.6 percent of all K-12 students in California.

What does it mean to "control for school size and student background" and why is this important?

Studies have shown that academic performance at individual schools is heavily influenced by the demographic characteristics of the student body. For example, students whose parents graduated from college tend to perform better on achievement tests than students whose parents did not complete high school. These characteristics are captured in schools' School Characteristics Index (SCI) value.

The EdSource study "controlled" for many of these factors, including parental education levels and socioeconomic status, as well as school size. As a result of these controls, EdSource was able to compare schools on an "apples to apples" basis, ensuring that results identified were not due to underlying demographic differences between students attending different types of schools.

Did EdSource adjust for self-selection bias?

Some researchers believe that charter school students are more motivated than traditional pubic school students because they need to affirmatively select a charter. They suggest that this "self-selection" bias may explain why some studies show charter school students perform better than traditional public school students. Unlike school size and parental socioeconomic status, self-selection bias is impossible to control for on a statewide basis with the data available. Therefore, the EdSource study did not adjust for it.

Why did EdSource control for school size and student background in its analysis of LAUSD, but not in its analyses of OUSD and SDUSD?

Since LAUSD has a greater number of charter schools, it can support a more rigorous statistical analysis. OUSD and SDUSD do not have enough charter schools to allow for this type of analysis, so performance data for these districts is presented without statistical adjustment for SCI and school size.

What is the difference between a CMO charter school and a non-CMO charter school?

CMOs (Charter Management Organizations) are primarily non-profit organizations that provide administrative support and instructional leadership for more than one charter school. Some of the best-known CMOs operating in California are Green Dot Public Schools, the Knowledge is Power Program (KIPP), and Aspire Public Schools. Non-CMO charter schools are not affiliated with a CMO.

What sources were used to measure student performance in this report?

The primary data sources for this report were the Academic Performance Index (API), the California High School Exit Exam (CAHSEE), the California Standards Tests, and Adequate Yearly Progress (AYP), which measures the percentage of students achieving proficiency on the state's academic standards. For a detailed explanation of the components used to calculate the API, see http://www.cde.ca.gov/ta/ac/ap/documents/infoguide06b.pdf.

What criteria do charters need to meet to satisfy state performance requirements for charter renewal?

According to California Assembly Bill 1137, which was enacted in 2003 and became effective in January 2005, charter schools in operation for four years or more must satisfy at least one of the following requirements to be eligible for renewal:

• Rank in Decile 4 or higher (in the top 70% of schools) on the statewide or similar schools API rankings in the prior year or in two of the last three years;
• Meet its API growth target (improvement goal) in the prior year, in two of the last three years, or in the aggregate for the prior three years; or
• Have its charter-granting agency determine that the school's academic performance is at least equivalent to the performance of the schools the charter students would have attended otherwise and other schools within the district serving similar students.

Schools that qualify for the Alternative Schools Accountability Model (ASAM), which is for schools serving a majority of at-risk students, are not required to satisfy any of these indicators. Instead they must select and satisfy three indicators of performance from a list of measures, such as student attendance, credit completion, and reading and math achievement.

How can parents learn more about the performance of a specific school?

The Ed-Data Partnership web site—www.ed-data.k12.ca.us—provides extensive information about every public school in California, including student performance and staffing information. Information on both charter and noncharter schools is available.

What is EdSource and who funded this research?

EdSource is an independent, impartial, not-for-profit organization whose sole mission is to clarify complex education issues and to promote thoughtful decisions about public school improvement. EdSource does not advocate or lobby and has developed a solid reputation as a credible and impartial source of K-12 education information. EdSource received a multi-year grant from Reed Hastings, Founder and CEO of Netflix, Inc. and a former President of the California Board of Education, to independently analyze and report annually on charter school performance, including: California's Charter Schools: 2008 Performance Update.

To find out more about the study findings and download the executive summary, click here.