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What are Microdata?
Microdata are composed of individual records containing information collected on persons and households. The unit of observation is usually the individual, but can be the household, family, etc. The responses of each person to the different census questions are recorded in separate variables. Microdata stand in contrast to more familiar "summary" or "aggregate" data. Aggregate data are compiled statistics, such as a table of marital status by sex for some locality. Microdata are inherently flexible. One need not depend on published statistics from a census that compiled the data in a certain way, if at all. Users can generate their own statistics from the data in any manner desired, including individual-level multivariate analyses.
- Data Liberation Initiative
List of surveys available through the DLI. All documentation is freely available. Data can be downloaded via the <odesi> interface.
A web-based data exploration, extraction and analysis tool. It provides researchers the ability to search for survey questions (variables) across hundreds of datasets held in a growing number of collections. <odesi> supports basic tabulation and analysis online, and allows for the downloading of most datasets into statistical software for further analysis. <odesi> provides unprecedented access to extensive collections of polling and social survey data. Key polling data collections include: Canadian Opinion Research Archive (CORA), Canadian Gallup, and Ipsos Reid. Statistics Canada's public-use survey data forms the core of <odesi>'s social survey data holdings. <odesi> is expanding its survey data to include other national and international data sources.
US and International
- ICPSR ( Inter-university Consortium for Political and Social Research)
ICPSR maintains a data archive of more than 500,000 files of research in the social sciences. It hosts 16 specialized collections of data in education, aging, criminal justice, substance abuse, terrorism, and other fields. Data and documentation can be downloaded directly; selected datasets can be analyzed online.
IPUMS-CPS is an integrated set of data from 48 years (1962-2009) of the March Current Population Survey (CPS). The CPS is a monthly U.S. household survey conducted jointly by the U.S. Census Bureau and the Bureau of Labor Statistics. Initiated in the 1940s in the wake of the Great Depression, the survey was designed to measure unemployment. A battery of labor force and demographic questions, known as the "basic monthly survey," is asked every month. Over time, supplemental inquiries on special topics have been added for particular months. Among these supplemental surveys, the March Annual Demographic File and Income Supplement (hereafter referred to as the March CPS) is the most widely used by social scientists and policymakers, and it provides the data for IPUMS-CPS.
Provides access to census microdata from 68 countries, comprising 211 censuses. IPUMS-International is an effort to inventory, preserve, harmonize, and disseminate census microdata from around the world. The project has collected the world's largest archive of publicly available census samples. The data are coded and documented consistently across countries and over time to facillitate comparative research. IPUMS-International makes these data available to qualified researchers free of charge through a web dissemination system. Access is free, but registration is required.
The Integrated Public Use Microdata Series (IPUMS-USA) consists of more than fifty high-precision samples of the American population drawn from fifteen federal censuses and from the American Community Surveys of 2000-2007. Some of these samples have existed for years, and others were created specifically for this database. These samples, which draw on every surviving census from 1850-2000, and the 2000-2007 ACS samples, collectively constitute our richest source of quantitative information on long-term changes in the American population. However, because different investigators created these samples at different times, they employed a wide variety of record layouts, coding schemes, and documentation. This has complicated efforts to use them to study change over time. The IPUMS assigns uniform codes across all the samples and brings relevant documentation into a coherent form to facilitate analysis of social and economic change.
- Uppsala Conflict Database
Uppsala Conflict Data Program (UCDP). After a period of trials the Conflict Data Project was properly established at the Department by the mid-1980s. It continuously collects data on armed conflicts. The definitions have gradually been refined primarily to fit scholarly requirements of global comparability. The definitions are designed so as to pick up the same phenomenon across time as well as across space. This makes the data useful for systematic studies of the origins of conflict, conflict dynamics and conflict resolution.
- World Values Survey
National surveys about values and beliefs.