Research libraries and data archives are now bursting with data ready to be analyzed. In numeric or statistical data collections, roughly speaking, there are two kinds of data resources in terms of the structure of data content and/or processing. One is aggregated data; and the other is unaggregated data, which is usually called microdata or machine-readable raw data. 

Microdata is mostly original data that contains every individual (e.g., person, company, etc.) record in the survey/research samples. Public Use Microdata Sample datafiles, mainly from U. S. Censuses and other relevant governmental surveys, so far account for the majority of microdata that have been used by researchers and other data users. The size of microdata is usually too huge to be available in print, thus computerized data storage and retrieval systems, as well as issues of file formats associated with various statistical software and operating systems, are heavily involved in working with microdata. This has made data services one of most challenging tasks in library services at academic and research libraries.

This site is developed to provide a guide to research data users and librarians who are currently or potentially involved in seeking, acquiring, using, and managing microdata files. On this site, a brief explanation of the content structure of microdata is provided so that you can decide whether or not microdata is what you are looking for. Resources regarding where to get microdata and how to get and/or use it are listed and annotated.  The guide is a gateway to microdata resources, which is intended to facilitate users in acquiring and using microdata of their interests, and also to serve as a reference tool for librarians who work in data services.

Except where otherwise indicated, original content in this guide is licensed under a  Creative Commons Attribution (CC BY) 4.0 license. You are free to share, adopt, or adapt the materials. We encourage broad adoption of these materials for teaching and other professional development purposes, and invite you to customize them for your own needs.