University of Akron, University Libraries: Guide to Accessing ICPSR Data

Guide to Accessing ICPSR Data

Where can I get more help?
Email ICPSR's official representative at the University of Akron.
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What is ICPSR?

The University of Akron is an institutional member of the Inter-University Consortium for Political and Social Research (ICPSR), located at the University of Michigan. ICPSR maintains and provides access to an archive of social science data in electronic format. Its holdings include data sets relevant to the study of political science, sociology, demography, history, economics, international relations, gerontology, public health, criminal justice, education and many other fields.

Who can access ICPSR data sets?

Students, faculty and staff at The University of Akron are welcome to use ICPSR data sets for their research projects. You must agree to the terms outlined in ICPSR's Responsible Use Statement before downloading any data sets. Some data sets are freely available to both members and non-members of ICPSR. Other data sets are restricted from use due to reasons of confidentiality; please consult ICPSR's information on Restricted Data if you wish to access a restricted data set.

Your computer needs to have a valid University of Akron IP (Internet) address in order to download ICPSR data sets. You can obtain a valid address by connecting from on-campus, dialing in directly to The University of Akron dial-in network, or connecting through the UA VPN (Virtual Private Network). The guide to Connecting to Online Library Resources from Off-Campus provides more information on the dial-in network and UA VPN.

How do I access and download ICPSR data sets?

The first step in accessing ICPSR data sets is to locate an appropriate study. You can do this by first searching the full data holdings, browsing by subject, or using the thesaurus.

The next step is to look at the abstract of the study. Information contained in the summary, time period, data source, sampling, and universe fields will help you to determine whether the study will meet your research objectives. Information contained in the data format field will help you to determine whether the data files can be used with your statistical software program. The collection notes field contains further information about the data set. Restrictions on use of the data are noted in the restrictions field.

If you choose to download the data set, you will first be prompted with information concerning authorization. Type in your email address, then click on the "click to continue" button.

Your next step is to download the appropriate elements of the data set. The basic elements of a data set are codebooks and data files. Codebooks provide information on the structure, contents, and layout of a data file. Generally, codebooks include a title page, bibliographic citation, data collection description, and codebook body. The codebook body describes the content of the data file and provides information on each variable contained in the data file. Codebooks are available for downloading in compressed and uncompressed PDF format files.

Print copies of some codebooks may also be found in Bierce Library's Reference Collection. To determine whether the library has a print copy of a particular codebook, do a title search for the study title in ZipLINK, the library's online catalog. To see a listing of codebooks held in the library's reference collection, do an author search for Inter-University Consortium for Political and Social Research in ZipLINK.

Most data files are ASCII fixed-format files. These files consist of rows and columns of alphanumeric characters. Some older data files are in ASCII format but were created for use with OSIRIS statistical software. OSIRIS data files must be used in conjunction with OSIRIS dictionary files. Data files are available for downloading in compressed and uncompressed formats.

Many data sets also contain data definition statements for specific software programs (e.g., SPSS, SAS). Data definition statements (also known as control cards) contain the syntax or program code needed to read raw data into a statistical package, such as SPSS or SAS. Data definition statements link the columns of alphanumeric data contained in the ASCII data files to the variables described in the codebook. It makes sense to download these data definition statements whenever available. Data definition statements are available for downloading in compressed and uncompressed formats.

Some data sets also contain SPSS portable (export) files or SAS transport files. SPSS portable files are not specific to a particular SPSS version or computer platform. These files can be opened directly in SPSS statistical software without the use of data definition statements. SAS transport files are also not specific to a particular computer platform, and can be opened directly in SAS statistical software without the use of data definition statements. In both cases, it is not necessary to download either the data definition statements or the data file; however, it is still necessary to download or refer to the codebook in order to make sense of the data. SPSS export files and SAS transport files are available for downloading in compressed and uncompressed formats.

Once you have downloaded the appropriate files of the data set, you can begin using these with your statistical software package.

How do I unzip compressed files?

ICPSR codebooks, data files, data definition statements, and export files can be downloaded in either compressed or uncompressed formats. Compressed files allow for faster downloading, but these will need to be decompressed on your computer or disk before they can be used. Follow these steps to decompress your files after you have saved them to your computer or local disk:

Use a decompression or unzip program that can handle .gz files. Both WinZip, a shareware program, and PowerArchiver, a freeware program, can handle these types of files.
Using your decompression program, locate the file that you wish to unzip by selecting "Open" from the toolbar, then looking in the directory to which you saved the file. Select the file, then click on "Open."
Click on the filename for the file that you wish to unzip, then select "Extract" from the toolbar. The program will prompt you to choose a directory in which to place the extracted file. You may want to choose c:\temp. Click on extract.
The file has now been decompressed or unzipped. Use SPSS, SAS or another statistical software program to use the data file.

Where can I get more help?

For assistance with locating appropriate studies and downloading data sets, please contact Dr. Steve Aby, saby@uakron.edu, ICPSR's official representative at the University of Akron, or James Nalen, jnalen@uakron.edu.

For technical assistance (e.g., unzipping files, creating data definition statements, reading data into statistical software programs, converting OSIRIS data files, using SPSS), please contact Al Herbert, herbert@uakron.edu, manager of Help Desk Services.

For help with statistical analysis, please consult with your instructor. ICPSR also offers a Summer Program in Quantitative Methods of Social Research.

For help with citing data sets, please refer to ICPSR's guide to Citing Electronic Data Files.