U.S. PIRLS data are made available in three versions, each of which includes student achievement data as well as student, teacher, school, and curricular background data. The differences between these versions is summarized in the table below and described in detail below it. At the bottom of this page is a description of data analysis resources that are available for analyzing these data files.
|Version||U.S. data for international variables||Other participating education systems’ data for international variables||Data for U.S.-specific variables (e.g., race/ethnicity, poverty)||Restricted data (e.g., access to school names and CCD ID)|
|1. PIRLS International data files (including U.S. data)||Yes||Yes||No||No|
|2. PIRLS U.S. national public-use data files||Yes||No||Yes||No|
|3. PIRLS U.S. national restricted-use data files||Yes||No||Yes||Yes|
PIRLS data for the United States and other participating education systems (including both countries and subnational entities, such as Canadian provinces, U.S. states, England, and Hong Kong) are available as part of the PIRLS International Database released for each round of PIRLS. The International Database consists of data files with the set of international variables that are common to all participating education systems, including the United States. The PIRLS International Database, its User Guide (describing the organization and content of the database) and supplements, and supporting materials (e.g., SAS/SPSS control files, international codebooks and data almanacs, international version of the background questionnaires, and released items) are available for download for each round of PIRLS from the TIMSS and PIRLS International Study Center website. This website also lists publications that may be helpful to data users (e.g., PIRLS User Guide for the International Database, PIRLS Assessment Framework and Specifications). Beginning in 2011, information that was previously included in the PIRLS Technical Report can be found in the PIRLS 2011 Methods and Procedures section of the TIMSS and PIRLS International Study Center website.
In addition to the information collected from the international background questionnaires and that appears in the variables of the PIRLS International Database, each country has the option to collect additional country-specific information. At each round of PIRLS, the United States has exercised the option to collect some additional U.S.-specific information that is not included in the PIRLS International Database. For example, additional U.S.-specific information includes the race/ethnicity of students and the percentage of public-school students eligible for the federal free and reduced-price lunch program. These U.S.-specific variables are available in the PIRLS U.S. national public-use data files. These public-use files for PIRLS 2001, 2006, and 2011 can be downloaded from the Data Products section of the NCES PIRLS website. Note that the PIRLS U.S. national public-use data files do not include international variables for countries other than the United States.
PIRLS U.S. national restricted-use data files include (a) the U.S.-specific variables that are available in the PIRLS U.S. national public-use data files, (b) complete, original data for the continuous variables that are converted into categorical data for confidentiality reasons on the public-use data files, and (c) the supplemental files that link restricted NCES school ID numbers to the school ID numbers as they appear in the publicly available Common Core of Data (CCD) or the Private School Universe Survey (PSS). Because the linking of these data reveal the identities of participating schools, the restricted-use data files are only made available to those who obtain a NCES restricted-use data license. Directions on how to obtain the license can be found at http://nces.ed.gov/pubsearch/licenses.asp.
PIRLS data files are quite complex on account of the study’s multi-stage sample design and use of imputed scores (also known as plausible values). These complexities can make analyzing the data challenging for users. To help users explore PIRLS data without having to master the technical complexities of the data files, NCES has developed a relatively simple, interactive online data-analysis tool: the International Data Explorer (IDE) . The IDE allows users to do descriptive analyses with all of the international variables for all participating education systems along with the U.S.-specific variables; however, it does not include U.S. restricted-use data.
Users who wish to do more sophisticated analyses, such as bivariate correlations and multivariate regressions, can use a free add-on application to SPSS called the International Database (IDB) Analyzer developed by the International Association for the Evaluation of Educational Achievement (IEA) that also appropriately accounts for the complexities of the data. The International Database (IDB) Analyzer can be downloaded for free from the IEA website. While the IDB Analyzer requires SPSS subscription, the IDE does not require SPSS for analyzing the data. Note that the IDB Analyzer's default is to use files from the international database. However, it is possible to use the IDB Analyzer to conduct analyses with the U.S.-specific variables if SPSS versions of the PIRLS U.S. national public-use data files or the PIRLS U.S. national restricted-use data files are uploaded to the IDB Analyzer or if U.S-specific variables are merged to a file from the international database.