The Source for Crime and Justice Data
Note:
If the Survey Documentation and Analysis (SDA) is available for a study, users will see a link to "online analysis" in the Search Results for that study. Under the study name and author, there may be up to four links: description, download, online analysis and related literature. Clicking on "online anaylsis" will take users to a page for the study from which they can access all SDA features. A clickable Online Analysis tab also appears on the description and download pages of relevant studies.

Analyze Data Online

Survey Documentation and Analysis (SDA)

A selection of NACJD data collections is available for online data analysis. This means that users can perform certain statistical procedures on the data, create custom subsets, or browse the codebook on the Web, without downloading the entire collection and importing the data into a statistical package.

  • Search for variables of interest in a dataset
  • Review frequencies or summary statistics of key variables to determine what further analyses are appropriate
  • Review frequencies or summary statistics for missing data
  • Produce simple summary statistics for reports
  • Create statistical tables from raw data
  • Create a subset of cases or variables from a large collection to save time and storage space downloading to a personal computer

Features of the Online SDA

This online Survey Documentation and Analysis uses the Survey Documentation and Analysis (SDA) program developed and maintained by the Computer-Assisted Survey Methods Program at the University of California, Berkeley. Online documentation for this system is available. In addition, NACJD offers a web-based SDA Tutorial; a video tutorial, An Overview of SDA and Its Features; and a webinar and corresponding PowerPoint slides, Analyze Data Online on Demand: An Introduction to SDA.

The following features of the online Survey Documentation and Analysis are currently available:

  • Browse the codebook for a dataset
  • Perform certain statistical procedures, such as:
    • List values of individual cases
    • Frequencies
    • Crosstabulations
    • Comparisons of means
    • Correlation matrix
    • Ordinary Least Squares (OLS) regression
  • Manipulate variables
  • Recode variables
  • Compute new variables
  • List newly created variables
  • Create customized subsets of selected variables and cases
  • Download the entire collection or a customized subset, including:
    • ASCII data file with optional delimiters
    • SAS, SPSS, or Stata setup files
    • Codebook customized for the selected subset

NACJD Collections Available for Use With SDA

  

Variable-Level Searching

The Social Science Variables Database (SSVD) enables ICPSR users to search for variables across datasets, compare results, and download data if desired.

Search results may be viewed individually, or in the context of the study and/or series to which they belong.

The SSVD currently includes variable-level documentation for approximately 2,000 studies, which represent about 40 percent of ICPSR's holdings that have setup files. This amounts to roughly 1.5 million variables.