Some caution about Census data on same-sex couples:

Yesterday I posted some results from a new Census study comparing married same-sex couples and married opposite-sex couples, and comparing both to unmarried same-sex couples. The study concluded that in many significant ways — including likelihood to be raising children, income, home ownership, education, and race — gay and straight married couples were very similar, and unlike unmarried gay couples. The study also furnished evidence for some surprises, like the possibility that lesbian couples might be less likely to get married (or consider themselves married) than gay male couples.

But there's a potential problem in at least some of the Census numbers, which are inconsistent with some of the work done by demographers who have studied same-sex couples. Gary Gates, a noted demographer and researcher at UCLA (and a gay-marriage supporter), writes in an email to me:

One of the take-aways from the [Census] report is that married same-sex couples look quite a bit like their different-sex counterparts. That may very well be true, but one reason for the similarity is that it's quite possible that a very large portion of the married same-sex couples are, in fact, different-sex married couples who miscoded their sex. I've attached a paper (presented at the same session of the Population Association of America conference as the Census paper) that describes the difficulties in interpreting the married same-sex couple data.

From other work I've done, we know that married same-sex couples are 2-to-1 female and that women are more likely than men to be in a partnership. This isn't very consistent with the Census findings. Our analyses suggest that the sex miscoding problem among married different-sex couples creates more male same-sex couple miscodes than female. That could explain the Census findings.

There are several other findings that are not consistent with information we have about differences between cohabiting same-sex couples who are or are not in legally recognized relationships. For example, in a paper I published recently in Demography (with Christopher Carpenter), we show that those in registered domestic partnerships (in CA) ["RDPs"] have higher income and education levels and are more likely to be white than those who are not registered. These are the same patterns we see among heterosexual couples (comparing married v. unmarried) and contradict the Census findings. We also find no evidence of higher rates of child-rearing for those in RDPs in men and modest evidence of differences among women. Granted, RDP and marriage are not the same, but folks should be very cautious in interpreting the Census findings.

I think it's a very positive step that the Census released an analysis of the same-sex spouses. But it's just a first step. Much more work is needed to better understand who the married same-sex couples are and how many are miscodes.

If Gates is right about the coding problems, the miscoding would have skewed the results in favor of similarities since opposite-sex couples would have been included in the "same-sex" data. So gay and straight couples may be alike in many of the ways the Census Bureau suggested, but the new Census data do not necessarily support that hypothesis. A lot more work is needed, including more work based on the 2010 Census itself. In the meantime, modesty and caution about this new Census data are in order — more modesty and caution than I used yesterday.

UPDATE: For some interesting historical background on an especially noxious Census error, see here.

Related Posts (on one page):

  1. Some caution about Census data on same-sex couples:
  2. New Census study comparing gay and straight married couples: