Statistical coherence of primary schooling in IPUMS-International integrated population samples for China, India, Vietnam, and ten other Asia-Pacific countries.

IPUMS-International www.ipums.org/international disseminates harmonized census microdata for more than 80 countries at no cost, although access is restricted to bona-fide researchers and students who agree to the stringent conditions of use license. Currently over 270 samples are available, totalling more than 600 million person records. Each year 15-20 additional samples are released, as more countries cooperate with the IPUMS initiative and the integration of 2010 round census samples is completed. With so much microdata so readily available, questions of data quality naturally arise. This paper focusses on the concept of statistical coherence over time for a single concept, primary schooling completed. From an analysis of the percentage completing primary schooling by birth year for pairs of samples for thirteen Asia-Pacific countries, we find outstanding coherence for four-China, Mongolia, Vietnam, and Indonesia-with mean differences of less than 0.5 percentage points, regression coefficient (b) ranging from 0.93 to 1.07 and R2 =.99. For the thirteen countries as a group there is considerable variation overall with mean absolute difference as high as 16 percentage points, b ranging from 0.62-1.44 and R2=.65-.99. As a whole, statistical coherence of primary schooling is outstanding. Nonetheless, to make expert use of the harmonized microdata, researchers are cautioned to carefully study the IPUMS integrated metadata as well as the original source documentation. National Statistical Offices not currently cooperating or that have not yet entrusted 2010 round census microdata are invited to do so.

THE IPUMS COLLABORATION: INTEGRATING AND DISSEMINATING THE WORLD'S POPULATION MICRODATA.

The Integrated Public Use Microdata Series (IPUMS) International partnership is a project of the Minnesota Population Center and national statistical agencies, dedicated to collecting and distributing census data from around the world. IPUMS is currently disseminating data on over a half-billion persons enumerated in more than 250 census samples from 79 countries. The data series includes information on a broad range of population characteristics, including fertility, nuptiality, life-course transitions, migration, labor-force participation, occupational structure, education, ethnicity, and household composition. This paper describes sample characteristics and data structure; the data integration process including the creation of constructed family interrelationship variables; the flexible dissemination system that enables researchers to build customized extracts of pooled census samples across time and place; and some of the most significant findings that have emerged from the database.

When Excessive Perturbation Goes Wrong and Why IPUMS-International Relies Instead on Sampling, Suppression, Swapping, and Other Minimally Harmful Methods to Protect Privacy of Census Microdata.

IPUMS-International disseminates population census microdata at no cost for 69 countries. Currently, a series of 212 samples totaling almost a half billion person records are available to researchers. Registration is required for researchers to gain access to the microdata. Statistics from Google Analytics show that IPUMS-International's lengthy, probing registration form is an effective deterrent for unqualified applicants. To protect data privacy, we rely principally on sampling, suppression of geographic detail, swapping of records across geographic boundaries, and other minimally harmful methods such as top and bottom coding. We do not use excessively perturbative methods. A recent case of perturbation gone wrong- the household samples of the 2000 census of the USA (PUMS), the 2003-2006 American Community Survey, and the 2004-2009 Current Population Survey-, an empirical study of the impact of perturbation on the usability of UK census microdata-the Individual SARs of the 1991 census of the UK-, and a mathematical demonstration in a timely compendium of statistical confidentiality practices confirm the wisdom of IPUMS microdata management protocols and statistical disclosure controls.

The North Atlantic Population Project: Progress and Prospects.

The North Atlantic Population Project (NAPP) is a massive database of historical census microdata from European and North American countries. The backbone of the project is the unique collection of completely digitized censuses providing information on the entire enumerated populations of each country. In addition, for some countries, the NAPP includes sample data from surrounding census years. In this article, the authors provide a brief history of the project, describe their progress to data and plans for the future, and discuss some potential implications of this unique data resource for social and economic research.

Big Data: Large-Scale Historical Infrastructure from the Minnesota Population Center.

The Minnesota Population Center (MPC) provides aggregate data and microdata that have been integrated and harmonized to maximize crosstemporal and cross-spatial comparability. All MPC data products are distributed free of charge through an interactive Web interface that enables users to limit the data and metadata being analyzed to samples and variables of interest to their research. In this article, the authors describe the integrated databases available from the MPC, report on recent additions and enhancements to these data sets, and summarize new online tools and resources that help users to analyze the data over time. They conclude with a description of the MPC's newest and largest infrastructure project to date: a global population and environment data network.