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Understanding the Academic Performance Index (API)

Last updated June 23, 2014

    A note about changes to California’s testing and accountability systems
    California’s testing and accountability systems will soon be changing significantly as a result of recent legislation and the state’s adoption of the Common Core State Standards.

    In 2013, Assembly Bill (AB) 484 suspended the state’s Standardized Testing and Reporting (STAR) Program to allow schools time to prepare for the new Smarter Balanced assessments, which are aligned to the Common Core standards, and transition to a new assessment system called the California Assessment of Student Performance and Progress (CAASPP). A law passed in 2012, Senate Bill (SB) 1458, called for significant changes to the composition of the state’s high school Academic Performance Index (API).

    In 2014, the California State Board of Education decided not to produce a Growth API for two years during the transition to the state’s new Common Core standards and Smarter Balanced assessments. At the same time, the Legislature has asked the State Board of Education and the California Department of Education to add additional measures of student progress to the Academic Performance Index for high schools. This process is expected to be completed in 2015-16.

    Details for the new assessment and accountability systems as well as the implementation of the new Common Core Standards are still being worked out, and each has its own timeline. We will provide an in-depth explanation of the new systems when more information is available.

    How these changes affect what you see on Ed-Data: Because most of these changes take effect in the 2013-14 school year, this article accurately explains the testing and accountability system for the data and reports currently posted on Ed-Data. However, the California Department of Education will not be posting a 2013 Base API, and schools will no longer be receiving ranks. Instead, in May 2014, the Department released a 3-year average API​ for schools and districts, as authorized by AB 484. New API and STAR/California Standards Test (CST) data will not be available for 2013-14.

    For more information, please see: Changes to California's K-12 Education System.


    The Academic Performance Index (API) is an annual measure of test score performance of schools and districts. The California Department of Education (CDE) calculates the API and disseminates the results directly to schools and districts as well as posting them on the CDE website.

    Public Schools Accountability Act (PSAA)
    ​In 1999, California passed the Public Schools Accountability Act (PSAA) as the first step in developing a comprehensive system to hold students, schools, and districts accountable for improving student performance. The program now includes a student testing system (STAR) and a high school exit exam (CAHSEE). These assessments are both aligned with academic content standards, and with an Academic Performance Index (API) for measuring progress. These comprehensive accountability standards put California in a good position to meet the provisions of the 2001 federal law known as No Child Left Behind (NCLB). They are the components the state uses for measuring adequate yearly progress (AYP).

    In fall 2004, the California Department of Education began issuing an “Academic Progress Report” (APR) that combines state and federal reporting requirements into a single document.

    The API is a single number on a scale of 200 to 1,000 that indicates how well students in a school or district performed on the previous spring’s tests. An API is calculated for the whole school plus its "numerically significant subgroups," including socioeconomically disadvantaged students, English learners, and students with disabilities.

    The system is on a two-year cycle that gives a "base" score for the first year and a "growth" score in the second year. The Base API, which is usually released in the spring (for example, 2013), comes from the previous spring's test scores (2012). The Growth API, released in October (2013), comes from 2013 spring test scores. The system was originally developed for, and applied to, individual school sites only. School districts received their first API scores in 2003 to meet the requirements of the federal No Child Left Behind (NCLB) law. Individual schools, with certain exceptions, have growth targets, but districts do not.

    API scores for schools of the same type (elementary, middle, and high) are ranked into "deciles," with 1 representing the lowest-performing 10% of schools and 10 the highest-performing 10%. Schools have two rankings: (1) a statewide ranking that compares each school with all other schools in the state of the same type, and (2) a Similar Schools ranking that compares each school with 100 others that have similar student populations and other characteristics.

    Components of the API

    The API is calculated using results of the STAR (Standardized Testing and Reporting) program and the California High School Exit Exam (CAHSEE). The Public Schools Accountability Act (PSAA) stated that the Academic Performance Index should include multiple indicators. Criteria other than test scores—such as school staff attendance and student graduation rates—were supposed to be added when deemed reliable. But so far the state has only used test score results. (Note: The integration of graduation rates and grade eight and nine dropout rates, originally scheduled to be part of the 2011 Base API, have been rescheduled to a future calculation. For more information, please see the CDE's API webpage.)

    In 2012-13, STAR consisted of four types of tests, but not all of them were used in the API. The four tests included the California Standards Tests (CSTs) which examine students' proficiency on academic content standards in a variety of subjects. STAR also included the California Alternative Performance Assessment (CAPA) for students with severe cognitive disabilities, the California Modified Assessment (CMA) for students for whom the CAPA and CSTs are not appropriate, and one test (Standards-based Tests in Spanish) taken by certain Spanish-speaking English learner students. The Spanish tests are not part of the API calculation, but the rest are. The weight of each of these tests in a school's API score varies depending on several factors, but the CSTs generally play the lead role. (See "Calculating the API," below.)

    Exceptions

    The test scores for students not continuously enrolled in a school since October of the school year are not counted in the school's API. (Continuously enrolled is defined as enrolled without a gap of more than 30 consecutive days.)

    Special Education students who are exempted and students whose parents requested that they not be tested are also not counted. Special education schools do not receive target information or rankings because of the marked differences in their educational missions and populations served. These schools are indicated with the letter C in the CDE database.

    Small schools with 11-99 students receive an API score; however, a score calculated from such a low number of students is considered statistically less reliable. These small schools do not receive a similar schools ranking.

    Smaller schools with fewer than 11 valid test scores and those that serve mostly high-risk students, such as continuation schools, are considered Alternative Schools Accountability Model (ASAM) schools. Previously, student performance for ASAM schools was measured in a different way. But in October 2010 the governor vetoed funding for data collection and reporting for ASAM schools. Due to the lack of funding, the CDE discontinued separate ASAM reporting for 2009-10 and now provides ASAM schools an API report under the regular API system—however, the CDE continues to designate schools as ASAM if they meet established criteria. ASAM schools receive an API and growth targets, but no ranking. These schools are indicated with the letter B in the CDE database.

    In some cases, if the school has some invalid data, the CDE cannot calculate a valid rank for the school. For these schools, the statewide rank will display as the letter I in the CDE database.

    Calculating the API

    The Academic Performance Index assigns one number to a school on a scale of 200 to 1,000, with a score of at least 800 as the goal. The first step in calculating the API is to divide a school's individual student scores in each subject into five performance bands. The performance bands for California Standards Test (CST) results are labeled advanced, proficient, basic, below basic, and far below basic.

    The next step is to apply weights to the percent of students with scores in each performance band (least weight for the lowest bands). These are summed to give a value for the subject.

    Then each subject area and test is given a weight within the index. The weights depend on which tests are given to each grade in each school. For example, a high school’s Base API includes CAHSEE results. (For more information, see the 2012-13 Academic Performance Index Reports Information Guide.)

    The Base API scores vary school by school, depending on students’ grade levels and the number of students tested. The calculation also depends on the number of valid test scores at the school.

    Finally, the resulting scores are added to become one number for each school—its API. A school district's API is the sum total of all the student (not school) scores. 

    A caveat: Although the API is meant as a measure of academic growth, it is not intended to track the school’s growth over several years. The meaningful comparison is within each annual API cycle, between the Base API and the Growth API, because the computation of the API is kept as similar as possible within each cycle.

    The incorporation of new elements into the index at the beginning of an API base/growth cycle can lead to unintentional or confusing fluctuations in API scores compared with scores from the previous cycle.

    The state adjusts API scores to compensate for the effect of those new elements. The mechanism for that technical adjustment is called the scale calibration factor. Even so, the CDE warns against tracking the scores year to year

    A better comparison is to look at whether a school or district consistently meets its growth targets or to consider the amount of growth year to year. Even within a cycle, the students represented in each year are different. For example, in a K–6 school, you have a group of 2nd–6th graders present in year one, but in year two the 2nd graders are new and the 6th graders from year one are gone. 

    Setting growth targets

    The State Board of Education set the statewide API target at 800 out of a possible 1,000. The Public Schools Accountability Act calls for most schools to improve their performance each year by 5% of the difference between their API and the statewide target of 800, with a minimum target of five points' growth. For example, a school with an API of 340 would have a growth target of 23. A school with an API between 691 and 795 would need to gain five points. A school with an API between 796 and 799 would have a growth target of the difference between its API and 800. A school that is at or above 800 is expected to stay above that threshold. Special education centers and schools without valid Base API scores have no growth targets.

    A school's Base API score plus its growth target becomes that school's goal for its next Growth API. The process repeats each year. In 1998-99, the first year of the API program, 13% of elementary schools, 11% of middle schools, and 5% of high schools reached or exceeded 800 on the Growth API. In most years since then, the percentages have edged upwards, though they declined slightly in 2013 for all schools statewide. In 2013, 56% of elementary schools, 50% of middle schools, and 31% of high schools scored at least 800 points on the Growth API:

    ​School Type ​2004 ​2005 ​2006 ​2007 ​2008 ​2009 ​2010 ​2011 ​2012 ​2013
    ​Elementary 27%​ ​32% ​35% ​36% ​41% ​48% ​51% ​55% ​59% ​56%
    ​Middle ​18% ​21% ​24% ​25% ​30% ​36% ​40% ​43% ​49% ​50%
    High​ ​8% ​12% ​14% ​15% ​17% ​21% ​25% ​28% ​30% ​31%
    All Schools​ ​23% ​27% ​30% ​31% ​36% ​42% ​46% ​49% ​53% 51%​
    Note: This table excludes schools in the Alternative Schools Accountability Model (ASAM), special education schools, and schools with fewer than 100 valid scores. ​ ​ ​ ​ ​ ​ ​ ​

    When the Growth API is calculated, a school gets more credit for improvements at the bottom of the performance range than the top, creating an incentive for schools to focus on their lowest-performing students. 

    School districts do not receive API scores under the Public Schools Accountability Act. However, to comply with the state's NCLB plan, API has been added as an additional criterion for school districts. The district Growth API, for 2011-12, must be at least 740 (or one point above the Base API if the Base API score already is 800 or above). For each subsequent year the required Growth API score for NCLB will increase by 30 points until it reaches 800 in 2013-14. Under NCLB, API scores are also given to county offices of education when they operate schools directly.

    Scores of subgroups

    Each school's "numerically significant" subgroups of ethnic, socioeconomically disadvantaged (SED) students, English learners, and students with disabilities must show the same improvement in performance. (SED is defined as students on the free/reduced-price lunch program or those whose parents did not receive a high school diploma.) The eight ethnic subgroups are Black or African American, American Indian or Alaska Native, Asian, Filipino, Hispanic or Latino, Native Hawaiian or Pacific Islander, white, and "two or more races." To be significant, a subgroup must have at least 100 students with valid test scores or be 15% of the school's tested enrollment with at least 50 students.

    The API growth target for each significant subgroup used to be 80% of the school's growth target (or one point growth in each subgroup score if the school's API was 800 or more). Because these targets did not address the need to narrow the achievement gap between the traditionally higher- and lower-performing subgroups, beginning in 2006 all subgroups must meet the school’s growth target of 5% of the difference between its API and 800, or a minimum of 5 points.

    Beginning with the release of the 2010 Base API, API scores are reported for all subgroups with 11 or more students. For previous years, API scores are reported only for subgroups that are numerically significant. Regardless of whether or not an API score is reported, only subgroups that are numerically significant receive API growth targets.

    Ranking the schools

    Schools are ranked in two ways: (1) statewide according to type and (2) compared with 100 schools with similar characteristics. These rankings are calculated from the Base API data and included in the Base API reports only.

    For the statewide ranking, the API scores are divided into 10 equal groups (deciles) for elementary, middle, and high schools. For each type of school, 10% of the schools are placed in each decile group; the groups are numbered from 1 (the lowest) to 10 (the highest). A school's statewide rank is the decile into which it falls.

    Schools with 1 to 99 test scores are grouped with the others according to grades served, but small schools' scores are not used to calculate rankings. School districts and ASAM schools also are not ranked.

    The PSAA also set up a mechanism, a school characteristics index (SCI), for comparing a school with its peers based on the challenges they face because of student demographics and some school and teacher characteristics. The SCI considers the following factors:

    Socioeconomic indicators (average parent education, percent of students participating in free/reduced-price meals);

    Percent of students who are English learners (ELs) or have been redesignated as fluent English proficient (RFEP);
    Percent of students from eight different racial/ethnic groups, including "two or more races";
    Percent of students with disabilities;
    Percent of students in the Gifted and Talented Education (GATE) program;
    Teacher credentials (percent of teachers who are fully credentialed, percent with emergency permits);
    Average class size in specific grade spans;
    Percent of students first attending the school this year (i.e., school mobility);
    Whether the school operates a multitrack, year-round educational program;
    Percent of enrollment in specific grade spans by grade span; and
    Percent of students in the Migrant Education Program.

    SCI values primarily reflect student demographics and, to a lesser extent, school and teacher characteristics. The lower a school's SCI value, the more likely the school is to have low test scores because of challenges such as low average parent education level, high poverty rates, and high percentages of English learners. For more statistical information regarding the calculation of the SCI, see http://www.cde.ca.gov/ta/ac/ap/documents/tdgreport1112.pdf.

    The SCI permits comparisons of student achievement among schools with similar characteristics and is used to prepare the Similar Schools Rank. To prepare the Similar Schools list, an SCI value is computed for schools of each type (elementary, middle, and high). Schools of the same type are listed in order of their SCIs. For a given school, 50 schools with an SCI immediately above and 50 immediately below the school are selected as the group for comparison. (If the SCI for a given school is in the top or bottom 50 of the statewide distribution, the group becomes the top or bottom 100.) The 100 schools are then sorted by their API scores, divided into 10 groups (deciles), and marked from 1 (lowest) to 10 (highest). The school's Similar School Rank is the decile in which it falls (which may be different from its statewide API decile ranking).

    ASAM and small schools with 11 to 99 valid scores do not get a Similar Schools Rank.

    Improvement grants

    Since California first enacted the Public Schools Accountability Act (PSAA) in 1999, the state has experimented with various approaches to interventions. The original PSAA included a voluntary intervention program called Immediate Intervention/Underperforming Schools Program (II/USP). It was designed for schools in the lower half of the API rankings that had not met their API growth targets.

    In 2001, lawmakers established another intervention program—the High Priority Schools Grant Program (HPSGP)—which focused on schools in the bottom 10% of the API rankings. Similar to the II/USP in expecting improved performance, this new program was more specific about schools’ and districts’ responsibilities to provide basic inputs, such as textbooks and credentialed teachers. The research firm hired to evaluate the II/USP and the HPSGP found that both programs had little effect on schools’ test scores. Neither II/USP nor HPSGP exist today--instead, California has shifted its attention to yet another intervention program, “Program Improvement,” based on Adequate Yearly Progress (AYP), created by the enactment of NCLB in 2002.

    An intervention program based on the API still remains, however. In 2006, the state created a $2.7 billion, seven-year intervention program as part of a settlement of a lawsuit over funding for K–12 schools and community colleges. Fully implemented in 2008–09, the Quality Education Investment Act (QEIA) focuses on participating schools with API scores in the lowest two deciles. Participating schools must meet annual benchmarks for ratio of pupils to teachers and counselors, teacher qualifications and experience, and API growth targets.

    2012-13 Update

    In May 2013, the CDE released 2012 Base API results as part of the 2011-12 API reporting cycle. The 2013 Growth API was released in August 2013. 

    The 2013 API reporting cycle saw some significant changes, including: 

    Elimination of Adjustments to Grades Eight and Nine General Mathematics Result
    In March 2013, the State Board of Education (SBE) eliminated the lowering of performance levels of students in grade eight or nine who take the CST in General Mathematics. In prior years, as part of the state's push for students to begin Algebra I in the 8th grade, the results for any student taking the CST in General Mathematics in grade eight or nine were adjusted downward. This was done by lowering the API credit by one performance level for a grade eight student record and two performance levels for a grade nine student record. As a result of the SBE decision, the scores of students taking the CST in General Mathematics will be included in the API without an adjustment.

    Exclusion of the Writing Portion of the CST in ELA
    Beginning in 2013, the writing portion of the English-language arts (ELA) tests for grades four and seven will be reported separately from the ELA scale scores for the California Standards Test (CST) and California Modified Assessment (CMA) and will no longer be included in the calculation of the API. This is to allow for faster turn-around of student performance data on the CSTs and CMA. To allow for appropriate comparisons to be made between 2012 Base and the 2013 Growth APIs, the 2012 ELA writing scores were removed for the production of the 2012 Base API.

    Use of CALPADS for Demographic Data
    Starting with the 2012–13 reporting cycle, all demographic data such as race/ethnicity, students with disabilities (SWD) status, English learner (EL) status, participation in the National School Lunch Program (NSLP), and parent education level, will be taken from the California Longitudinal Pupil Achievement Data System Operational Data Store (CALPADS ODS). In prior years, these data were obtained from the Standardized Testing and Reporting (STAR) student answer document. For the calculation of the 2012 Base API, if the statewide student identifier (SSID) on the STAR or California High School Exit Examination (CAHSEE) student answer document was missing or did not match a student record in CALPADS ODS, the demographic data on the student answer document was used.

    The testing program changes every year. As more indicators of student performance are developed or are determined to meet technical specifications, they may be added to the API. Other components may change to meet the accountability requirements under the federal NCLB law. The evolving criteria for the API may affect how schools analyze and adapt their efforts to improve student performance in the future.

    For more information on these changes as well as the Department's work to develop new indicators for the High School API, please see the CDE's API page.

    All contents copyright © 2014, Education Data Partnership. All rights reserved.

    Ed-Data is a partnership of the California Department of Education, EdSource and the Fiscal Crisis & Management Assistance Team (FCMAT) designed to offer educators, policy makers, the legislature, parents, and the public quick access to timely and comprehensive data about K-12 education in California.