The American Community Survey (ACS) Public Use Microdata Sample (PUMS) files show the full range of population and housing unit responses collected on individual ACS questionnaires. For example, they show how respondents answered questions on occupation, place of work, and so forth. For a complete list of Subjects in the PUMS, visit PUMS Documentation. The PUMS files contain records for a subsample of ACS housing units and group quarters persons, with information on the characteristics of these housing units and group quarters persons plus the people in the selected housing units.
Changes to Group Quarters Methodology
In 2011, the Census Bureau implemented a new whole person imputation-based methodology to improve the estimates for small areas for the group quarters population. The amount of imputation results in almost twice as many group quarters person records present in the ACS microdata. The new process impacts the PUMS files starting with the 2011 ACS 1-year PUMS, with the number of group quarters person records almost doubling. The responses provided on the PUMS file for the imputed group quarters records are actual answers to questions donated by group quarters sampled records. Learn more about Group Quarters Small Area Estimation.