Gay Marriage Data

By Eric Crampton 06/08/2015


The latest data on civil unions and marriages is out.

What do we learn?

  • Civil unions are far less preferred to marriage, both by same and opposite-sex couples. 
    • In no year did civil unions exceed one percent of the number of marriages for opposite-sex couples.
    • When gay marriage was recognised, the number of same-sex civil unions plummeted. Prior to September 2013, there were an average of 44 same-sex female civil unions per month, and 30 male civil unions per month. After, both dropped to an average of just over three per month.
  • Women like marriage more than men. 1360 female couples formed civil unions since 2006, and 1003 female couples have been married since 2013. 1001 male couples formed civil unions and 751 male couples married over the same period.
  • The average number of opposite-sex marriages in the two years prior to gay marriage was 5631 per month. In the two years since gay marriage, that dropped to 5479 per month. 
    • A t-test shows no significant difference from the before period to the after period. So gay marriage hasn’t broken heterosexual marriage, or at least the difference isn’t yet statistically significant. Doing it properly would require controlling for time trends, but I doubt would change anything. The time trend was slightly negative on the number of opposite-sex marriages prior to the change, and remained slightly negative after.