Skip Navigation

Confidentiality and Disclosure Limitations


In accordance with NCES standard 4-2 (2012 Revision of NCES Statistical Standards: Final), confidentiality analyses for the United States were implemented to provide reasonable assurance that public-use data files issued by the IEA and NCES would eliminate the disclosure of individual U.S. schools, teachers, or students. Potential disclosure can occur when the released data are compared against publicly available data collections that contain similar demographic information. All TIMSS and TIMSS Advanced 2015 participants were assured that their data would be confidential. Data security and confidentiality were maintained throughout all phases of the study, including data collection, data creation, data dissemination, and data analysis and reporting.

Statistical disclosure control (SDC) measures that were implemented on the TIMSS national data included the identifying and masking of potential disclosure risks for TIMSS schools and adding an additional measure of uncertainty of school, teacher, and student identification through random data swapping.1 The SDC's for the Florida state sample were limited to random data swapping because the Florida microdata are only released via restricted-use license. All procedures were carefully conducted and reviewed by NCES to ensure the protection of respondent privacy while preserving the integrity of the data.

1 The NCES standards 4-2-1 through 4-2-12 (Revised 2012) ( provide the guidelines and methodology required to ensure data confidentiality for data dissemination. Perturbation disclosure limitation techniques are conducted to protect individually identifiable data. For public-use data files, NCES requires analysis and subsequent perturbations to be performed that minimizes the possibility of a user matching outliers or unique cases on the file with external (or auxiliary) data sources. Because public-use files allow direct access to individual records, perturbation (such as random data swapping) and coarsening disclosure limitation techniques may both be required (Standard 4-2-8).