The U.S. Census Bureau released Sept. 27 new statistics on same-sex couple households in the United States. Revised estimates suggest there are about 646,000 same-sex couple homes, a drop from the 900,000 originally reported earlier this year.
"We started reviewing the data… and it became apparent that these numbers did not look consistent with the American Community Survey," said Martin O'Connell, chief of the U.S. Census Bureau's Fertility and Family Statistics Branch. "It took about two months to figure out what exactly was the problem, and we found [ it ] was the form."
Two forms were used to collect 2010 census data. The first, a one-page document delivered by mail, was straightforward with questions stacked vertically. The second form stretched across two pages and required respondents to 'hop around' as they answered; this form was administered in-person.
Researchers found that people who used the two-page, or matrix, formdisplayed a larger margin of error when it came to reporting sex. People named John were listed as female, while Susans had checked "male."
About one-quarter of all registered same-sex couples completed matrix forms, and O'Connell's team believes form confusion led to an overcount. As such, the sex for obviously gender-specific names like Robert or Emily was changed, while more neutral monikers such as Jamie or Morgan were left alone. The shifts increased the number of heterosexual couples, downsizing the same-sex couple count.
Revised U.S. Census Bureau data says there are 646,464 same-sex couple households in the United States. Of these, 514,735 are unmarried partner households, and 131,729 can be identified as spousal homes.
While the new estimates are smaller than those originally reported, they still mark an 8.8 percent increase from 2000's data. That year, 594,391 same-sex households were identified.
Illinois, for its part, saw fairly dramatic changes with the release of revised data. It is now believed there are 23,049 same-sex households in the state; that marks a sharp contrast with the 32,469 reported earlier this year.
O'Connell said states with historically low response rates, such as Illinois, were more likely to experience reporting errors. These states used the complicated matrix form as part of door-to-door outreach efforts.
The U.S. Census Bureau made headlines this August by claiming the number of same-sex households in Illinois jumped by 40 percent between 2000 and 2010. The bureau's new numbers, however, suggest only a 0.7-percent increase over the last decade.
New data says 19,442 of Illinois' same-sex households identify as unmarried partners, while 3,607 say they're married spouses. All 2010 census data was collected before Illinois began offering civil unions.
Currently, 52 percent of all of Illinois' same-sex households are male ( 12,068 ) , while 48 percent identify as female ( 10,981 ) .
State-by-state comparisons are available at www.census.gov, but city-level and countywide data is not open to the public.
"The information, once we get below the state level, could be very, very problematic in terms of [ confidentiality ] ," O'Connell said. "There may be some small cities where if the number was published, one could readily identify that gay couple with the child. The last thing we'd want to do when publishing census data is possibly pinpoint or identify a person."
For more information, including comprehensive statics, reports and maps, http://visit www.census.gov .