St. Joseph Community Partnership Fund

PolicyLink and PERE 104 An Equity Profile of Orange County Summary measures from IPUMS microdata About IPUMS microdata Although a variety of data sources were used, much of our analysis is based on a unique dataset created using microdata samples (i.e., "individual-level" data) from the Integrated Public Use Microdata Series (IPUMS), for four points in time: 1980, 1990, 2000, and 2012 through 2016 pooled together. While the 1980 through 2000 files are based on the decennial census and cover about 5 percent of the U.S. population each, the 2012 through 2016 files are from the American Community Survey (ACS) and each only cover about 1 percent of the U.S. population. Five years of ACS data were pooled together to improve the statistical reliability and to achieve a sample size that is comparable to that available in previous years. Survey weights were adjusted as necessary to produce estimates that represent an average over the 2012 through 2016 period. Compared with the more commonly used census "summary files," which include a limited set of summary tabulations of population and housing characteristics, use of Data and methods the microdata samples allow for the flexibility to create more illuminating metrics of equity and inclusion, and provide a more nuanced view of groups defined by age, race/ethnicity, and nativity in each region of the United States. A note on sample size While the IPUMS microdata allow for the tabulation of detailed population characteristics, it is important to keep in mind that because such tabulations are based on samples, they are subject to a margin of error and should be regarded as estimates— particularly in smaller regions and for smaller demographic subgroups. In an effort to avoid reporting highly unreliable estimates, we do not report any estimates that are based on a universe of fewer than 100 individual survey respondents. Geography of IPUMS microdata A key limitation of the IPUMS microdata is geographic detail. Each year of the data has a particular lowest level of geography associated with the individuals included known as the Public Use Microdata Area (PUMA) for years 1990 and later, or the County Group in 1980. PUMAs are generally drawn to contain a population of at least 100,000, and vary greatly in geographic size from being fairly small in densely populated urban areas, to very large in rural areas, often with one or more counties contained in a single PUMA. While the geography of the IPUMS microdata generally poses a challenge for the creation of regional summary measures, this was not the case for Orange County, as the geography of Orange County could be assembled perfectly by combining entire 1980 County Groups and 1990, 2000, and 2010 PUMAs.

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