Same sex households in the United States census: measurement issues and substantive results

Howard Hogan, U.S. Census Bureau
Martin T. O'Connell, U.S. Census Bureau

This paper addresses the measurement same-sex couple households from the 2010 Census and the related American Community Survey (ACS). Initial comparisons between the 2010 Census and the ACS indicated the 2010 Census number was 52 percent higher than the ACS estimate. Investigation indicates that the questionnaire design of the 2010 Census for the field data collection phase caused sufficient errors in recording sex to inflate the census counts, especially for the numbers of same-sex spousal households. These errors may have included mismarks of male/female on the questionnaire or errors in the optical reading of the marks. These errors would tend to misclassify an opposite-sex couple as a same-sex couple. A very small percentage of these errors had a significant impact on the overall estimate of same-sex couples. This paper estimates that 28 percent of all same-sex couple households in 2010 Census tabulations are likely to be opposite-sex couple households. This problem is more severe for those couples who reported being spouses than unmarried partners. This problem was most evident for households in the non-response follow-up (NRFU) phase of data collection where one partner’s sex in an opposite-sex household was incorrectly marked or captured in the processing phase, resulting in a same-sex couple household. As the ratio of opposite-sex to same-sex spousal households is much greater than the ratio of opposite-sex to same-sex unmarried partner households, the effects of these errors are disproportionately greater on the numbers of same-sex spouses than unmarried partners. The paper presents both the methodological issues in estimating the true number of same-sex households and presents the new estimates.