Data Prospects : IPUMS - International 8 Matt Sobek

The Integrated Public Use Microdata Series (IPUMS) is a suite of population data projects developed at the Minnesota Population Center of the University of Minnesota. The largest of these, IPUMS-International, is the world’s most extensive collection of publicly accessible population microdata. Related IPUMS databases consist of U.S. census and survey data and historical census data from Europe and North America (Sobek et al. 2011; Ruggles 2014). All IPUMS data can be accessed at no cost by qualified researchers. The IPUMS projects share a number of key characteristics. Each record describes a person, and those individuals are organized into households. The projects follow a similar approach to data harmonization, documentation and dissemination. Common variables are coded and labeled consistently, and documentation describes comparability issues for each of these harmonized variables. All of this information is presented via a web interface that limits the display to a user’s selected samples of interest. A data extraction system allows researchers to select only the variables and samples they require, defining a customized pooled dataset that they download for analysis on their own desktop. The system delivers the individuallevel data on specific persons, not tables or other summary measures. Because variables are harmonized across time and place, IPUMS is optimized to support comparative research. This chapter focuses on the largest of the Minnesota data projects: IPUMS-International (henceforth, simply “IPUMS”). The database currently contains information on 560 million people in 79 countries. For most countries IPUMS provides information directly relevant to the study of both internal and international migration, such as place of birth, prior residence, and duration of residence. The chapter starts by describing some of the attributes of IPUMS owing to its nature as census data processed for scientific use. The temporal and geographic scope of the series is discussed next, followed by the general topical coverage of the variables. Most of the remaining discussion concerns the specific migration data available in IPUMS. The chapter concludes with a brief note on data quality and a discussion of potential research directions with these data.