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3. Data Description and Empirical Specification
Estimation is carried out on the US Census data for the year 2000, specifically its fivepercent
sample “5% IPUMS data” (a 1-in-20 national random nationwide population), which
provides -- in addition to standard samples of heterosexual individuals -- detailed demographic,
labor and income information on the largest sample of gay and lesbian partners. Unmarried “heads”
and “unmarried partners” and a random sample (twenty percent) of married “heads” and “spouses”
were extracted from the Census using the variables “relationship to household head” and “marital
status’. Records in these files were subsequently matched by means of the household identification
code “serial” to create a single observation for each couple. Using the variable “sex”, couples with
the head and the partner sharing the same gender were then identified as same-sex couples, gay and
lesbian, and those with opposite gender as heterosexual couples. Individuals with imputed values
for sex, marital status, and relationship to household head were excluded from our samples. This
procedure is crucial to our purposes, to extract actual same-sex couples from the 2000 US Census.
As documented in Black et al. (2006), Jepsen (2007), and in subsection 4.2 below, this method
prevents heterosexual couples from being identified as homosexual, which could occur on account
of a 2000 Census recoding error.
In the Census, gays and lesbians are identified by their cohabiting relationship, a household
being recorded as a same-sex union if the “relationship to head” is specified as “unmarried partner”,
so that single gays or lesbians cannot be recovered. This limitation is of less concern to us since our
analysis is exclusively of couples. However, most economic studies on homosexuals use Census
data, from either 1990 or 2000. Others (e.g., Black et al., 2003; Blandford, 2003) use data from the
General Social Survey (GSS), in which one can identify single gays and lesbians. Nevertheless, the
GSS’s homosexual sample comprises far fewer observations (around three hundred total) thanthe
Census data, and sexual orientation in the GSS is inferred from self-reported sexual activity,
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