Solving the problem of data in psychometrics: An introduction to the Item Response Warehouse (IRW)

In contrast to other quantitative disciplines, psychometric research tends to use a relatively small amount of empirical data. This limits the development of new methods and recommendations for best practices in applied settings. The Item Response Warehouse (IRW) is designed to address these challenges through the collection and standardization of a large volume of item response datasets in a free and open-source platform for researchers. We describe key elements of the data standardization process and provide a brief description of the 598 datasets in the current iteration of the IRW (version 12.0). We describe how to access the data through both the website and an API, and offer a brief tutorial with example R code illustrating how to download data from the IRW and use it in standard psychometric analyses. We conclude with a discussion of the IRW as a resource for ongoing research in psychometrics and related fields.