Gay Marriage, state by state: a tipping point

This story did not post correctly, but just click the title to get the graphs etc. It is very interesting data!


Gay Marriage, State by State: A Tipping Point?
by Andrew Gelman @ 10:56 PM
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Jeff Lax and Justin Phillips put together a dataset using national opinion polls from 1994 through 2009 and analyzed several different opinion questions on gay rights. Here I'm going to talk about their estimates of state-by-state trends in support for gay marriage.

In the past fifteen years, gay marriage has increased in popularity in all fifty states. No news there, but what was a surprise to me is where the largest changes have occurred. The popularity of gay marriage has increased fastest in the states where gay rights were already relatively popular in the 1990s.

In 1995, support for gay marriage exceeded 30% in only six states: New York, Rhode Island, Connecticut, Massachusetts, California, and Vermont. In these states, support for gay marriage has increased by an average of almost 20 percentage points. In contrast, support has increased by less than 10 percentage points in the six states that in 1995 were most anti-gay-marriage--Utah, Oklahoma, Alabama, Mississippi, Arkansas, and Idaho.

Here's the picture showing all 50 states:



I was stunned when I saw this picture. I generally expect to see uniform swing, or maybe even some "regression to the mean," with the lowest values increasing the most and the highest values declining, relative to the average. But that's not what's happening at all. What's going on?

Some possible explanations:



- A "tipping point": As gay rights become more accepted in a state, more gay people come out of the closet. And once straight people realize how many of their friends and relatives are gay, they're more likely to be supportive of gay rights. Recall that the average American knows something like 700 people. So if 5% of your friends and acquaintances are gay, that's 35 people you know--if they come out and let you know they're gay. Even accounting for variation in social networks--some people know 100 gay people, others may only know 10--there's the real potential for increased awareness leading to increased acceptance.

Conversely, in states where gay rights are highly unpopular, gay people will be slower to reveal themselves, and thus the knowing-and-accepting process will go slower.

- The role of politics: As gay rights become more popular in "blue states" such as New York, Massachusetts, California, etc., it becomes more in the interest of liberal politicians to push the issue (consider Governor David Paterson's recent efforts in New York). Conversely, in states where gay marriage is highly unpopular, it's in the interest of social conservatives to bring the issue to the forefront of public discussion. So the general public is likely to get the liberal spin on gay rights in liberal states and the conservative spin in conservative states. Perhaps this could help explain the divergence.

Where do we go next in studying this?

- We can look at other issues, not just on gay rights, to see where this sort of divergence occurs, and where we see the more expected uniform swing or regression-to-the-mean patterns.

- For the gay rights questions, we can break up the analysis by demographic factors--in particular, religion and age--to see where opinions are changing the fastest.

- To study the "tipping point" model, we could look at survey data on "Do you know any gay people?" and "How many gay people do you know?" over time and by state.

- To study the role of politics, we could gather data on the involvement of state politicians and political groups on gay issues.

I'm sure there are lots of other good ideas we haven't thought of.

Further discussion (and another pretty graph) here.




...see also gay rights