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Methodology and Technical Notes

Common Core of Data survey system. The State Nonfiscal Survey of Public Elementary/ Secondary Education, the Local Education Agency Universe Survey, and the Public Elementary/Secondary School Universe Survey are the nonfiscal components of the Common Core of Data (CCD) survey system. State Education Agencies (SEAs) report these data annually to the National Center for Education Statistics (NCES).

Participation in 2010–11. SEAs report nonfiscal data through the Department of Educationís EDFacts collection system. The 50 states, the District of Columbia, Puerto Rico, the U.S. Virgin Islands, and the Bureau of Indian Education participated in EDFacts for the 2010–11 school year; Guam and the Commonwealth of the Northern Mariana Islands reported directly to the CCD. The Department of Defense schools and American Samoa did not report data for the 2010–11 school year.

States report data to the EDFacts collection system through multiple file groups that fall into different reporting schedules throughout the year. The 2010–11 school year EDFacts collection of CCD data opened in January 2011. Depending on the specific variable or state, the data for the original 1a version of the report were extracted from EDFacts between January 21, 2011 and November 15, 2011. In June 2012, NCES conducted a special collection effort to improve data quality on the 2010–11 school universe file. This revised report includes corrections made by states resulting from this special collection effort which were extracted from EDFacts on July 18, 2012. Further updates from states may be included in subsequent file releases.

Totals. "United States" and "reporting states" totals in the tables include only the 50 states and the District of Columbia. These totals exclude data from the Bureau of Indian Education, DoDEA, Puerto Rico, or the other jurisdictions of American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, or the U.S. Virgin Islands.

Missing data. Not all states collect and report all of the data items requested in the CCD surveys. National Center for Education Statistics (NCES) attempts to correct missing data first by drawing on other sources. For example, a state may be unable to report data during the collection period, but publish them later, through a written report or website. NCES imports data from these other published sources to complete missing directory items. NCES may carry some information, such as address or telephone number, forward from a prior yearís report if it is missing in the current year. In general, NCES does not carry forward prior year statistical information, such as the number of students in membership, to replace missing data items. An exception was made in 2010–11 for the DoDEA schools and American Samoa, neither of which reported data for the 2010–11 school year; the numbers and statuses of schools in these jurisdictions were carried over from prior year files and all the other data items were left as missing.

While NCES does not impute (replaces a nonresponse with a plausible value) missing items in the Public Elementary/Secondary School Universe Survey (used in this report) or the Local Education Agency Universe Survey, NCES imputes some missing items in the State Nonfiscal Survey of Public Elementary/Secondary Education. When reporting results, NCES treats missing data within individual states differently than it treats missing data across all states and the District of Columbia. In order to report a state total of an item, the SEA must have reported at least 80 percent of possible cases. If information is missing for some, but no more than 15 percent, of possible cases (e.g., schools) across the 50 states and District of Columbia, NCES calculates totals and identifies them as "reporting states" totals (rather than totals for the United States).

The EDFacts collection system accepted blank responses in 2010–11 school year reports and did not require that states distinguish among missing, not applicable, and "zero" values. NCES used statistical editing procedures to identify responses as missing, not applicable, or zero after the fact, but it is possible that some blank responses were categorized incorrectly.

Data quality. NCES performed extensive quality review of all CCD data submissions. Data editors ask state CCD coordinators to correct or confirm any numbers that appear out of range when compared with other statesí data or with the stateís reports in previous years. If no explanation is forthcoming for anomalous data, NCES will either edit the value (as an example, replace a reported value with the sum of detail) or change it to missing. For example, if a state reported a schoolís enrollment of 12th-grade students that was substantially larger than the enrollment of 11th-grade students in the previous year, and the state could not explain the discrepancy, NCES would change the reported number of 12th-grade students to missing.

NCES also applies additional data edits to all three data files to reduce data anomalies. For example, in 2010–11, some states reported more full-time equivalent (FTE) counts at the school level than the local education agency (LEA) level and the states confirmed that the LEA figures were accurate. NCES edited the FTE data at the school level to match the data at the LEA level by proportionately adjusting the counts.

Special collection effort to improve data quality. In May 2012, NCES became aware of data errors for key data items for several schools on the published version of the SY 2009–10 school file; in some cases these errors also affected district level data on the published 1a version of the LEA universe files for SY 2009–10. As a result, NCES conducted an in depth quality review of both the school and LEA universes for both the published SY 2009–10 school and LEA universe files and not yet published SY 2010–11 school and LEA universe files. During this review, NCES developed a revised editing strategy that more accurately identified data items that were likely to have errors. The review focused on school and school district enrollment, grade 12 enrollment, and free and reduced price lunch variables and related ratios such as pupil/teacher ratio, percent of enrollment from grade 12, and percent of students eligible for free and reduced price lunch. In the past data items were only compared to the reported data from the prior year for each school or LEA. The revised methodology used data from multiple years and was applied to both the reported data items and related ratios. Specifically, an average variation over the prior 4 years was computed based on the differences between each year and the other 3 years. Then, the average variation between the target year and the four preceding years was computed based on the differences between target year and each of the 4 prior years. The average variation for the target year was compared to the average variation among the prior years; cases with large differences were flagged as potential errors. Additionally, a requirement was added that in order for an item to be identified as a potential error, both the count and a related ratio must be identified as potential errors. For example, for total student membership to be flagged as a potential error, both total membership and a related ratio, such as pupil/teacher ratio, must be flagged.

NCES subsequently applied this revised editing methodology to both the SY 2009–10 and SY 2010–11 school and LEA universe files. This resulted in identification of over 1,000 questionable data items in the school and LEA universe files for both school years. In June 2012, NCES generated edit reports for each state with affected data items and provided these to the SEA EDFacts coordinators asking them to submit corrected data or provide a justification for the large variation in the reported data. In most cases, SEAs provided corrections of the data items in question or provided an acceptable explanation for the apparent data anomaly. CCD Survey staff reviewed the revised data and explanations submitted by SEAs to ensure that revised data were of acceptable quality and that any unchanged items were adequately explained. For data items that were not adequately resolved CCD Survey Staff applied suppression codes indicating that these items did not meet NCES data quality standards. This report is based on the 2010–11 provisional version 2a data file, which contains revisions to only the data items that NCES identified as potential errors during this process.

School and agency operational and membership status. In order to ensure continuity over time, the CCD includes schools and agencies that may not be operating during the school year reported. "Inactive" schools and agencies are those that are closed temporarily with the intention that they will be reopened; these schools and agencies retain their original NCES identification code. When an LEA or school ceases to operate permanently, the CCD includes these as "Closed" schools or agencies for one school year after closing. "Future" schools are those that are scheduled to open, but have not yet begun to operate.

Some operational schools or agencies may legitimately not report students. A vocational school or a LEA operating only vocational schools may provide classes for students from a number of regular schools or school districts. In this case, the students are usually reported in the membership of their school of record, and the vocational school (identified as a "shared time" school) shows no student membership. It is also possible that an operational school that is not "shared time" can be reported with no membership. For example, the number of students may be missing, or the school could have not yet enrolled students when it was reported.

Reportable programs. NCES makes every effort to ensure that the CCD and EDFacts files agree in the numbers of schools they contain. Because the EDFacts< system collects data for a number of programs in the U.S. Department of Education, it includes some entities that do not meet the CCDís definition of a school (e.g., a self-contained magnet or alternative program within a school is counted as a separate school in EDFacts, but not in the CCD). A total of 301 of these entities, referred to as "reportable programs," were excluded from this report.

School type edits. Beginning with the 2007–08 school year, the CCD edits the reported school type if it does not agree with the CCD definition. For example, if a school name indicated that it focused primarily on the needs of students with disabilities or if the state reported that at least 80 percent of the students enrolled in the school had special education individual education programs (IEPs), NCES reclassified the school as a special education school. (The number of students with IEPs was reported to EDFacts collection system at the school and LEA level, but the CCD only contains IEP data at the LEA level.) Similarly, if a school name suggested that it was a vocational or alternative school, NCES researched the school through different resources (e.g., school website or education association) or by calling the school to determine if the school should be reclassified as a vocational or alternative school. NCES asked CCD Coordinators to review these reclassifications, and if they provided evidence that a school met CCD criteria for the originally reported type, the school type was not changed.

Agreement across survey levels. For LEA membership counts, SEAs report students in the LEA that initially receives funds for their education and has responsibility for their education. For school membership counts, SEAs report students in the school they attend. Each student may only be reported for a single school and for a single agency. Some students receive a public education outside a regular school district (for example, they may attend a state-operated residential school). Some students in a regular school district may not be served by a school. Hospitalized and homebound students, for example, may be reported in the membership for a regular school district but not for any of the districtís schools. NCES derives the numbers of students and staff shown in the tables for each CCD First Look report from the survey represented in that report. Therefore, the numbers may differ across reports. NCES considers the numbers reported in the State Nonfiscal Survey of Public Elementary/Secondary Education to be the official statistics for a state.

Staff counts. All staff counts (including teachers) are reported in FTE units. This is the amount of time required to perform an assignment stated as a proportion of a full-time position. It is computed by dividing the amount of time an individual is employed by the time normally required for a full-time position.

For more detailed explanations on CCD methodology and technical information, see the documentation to the NCES Common Core of Data School Universe Survey: School Year 2010–11, which can be accessed at