Poblano ain’t perfect.

How Opinion on Same-Sex Marriage Is Changing, and What It Means

By NATE SILVER, The New York Times

March 26, 2013, 10:10 am

In 2011, I published a model projecting ballot initiative results for same-sex marriage based on two scenarios: one which assumed a linear increase in support, and the other which assumed an accelerating trend.

In general, the more conservative linear model was closer to the mark in forecasting the 2012 results. It predicted that 48.8 percent of voters would vote in support of same-sex marriage on average among the five states, fairly close to the actual figure of 50.1 percent. By contrast, the accelerated model predicted that 53.6 percent would vote to support same-sex marriage in these states.

This would tend to suggest, as the polling data does, that while the increase in support for same-sex marriage may be impressive, it has mostly been a consequence of support building slowly and steadily over time, rather than there having been sudden reversals in public opinion.

While ballot wording will remain a complicating factor, it is possible to be more precise about the contours of public opinion in individual states. Our 2011 model looked at only two demographic factors specific to each state: how many voters in those states were regular churchgoers, and how the voters rated themselves on an overall conservative-liberal scale. There are clearly a number of other factors that also affect opinion on same-sex marriage, however, most notably age, race, urbanity and education levels. The statistical challenge is that it is tough to reliably account for all of these demographic factors (while at the same time controlling for other factors like the year in which the measure was on ballot) given a relatively small sample of 39 ballot measures since 1998.

This model predicts the results of the 2012 ballot propositions quite accurately, accounting for some of the more subtle demographic distinctions that we had lost previously. (For instance, Maine is a relatively old state and a rural one, which may account for why it initially rejected same-sex marriage in 2009 despite being liberal and irreligious.) It projects that voters in roughly 20 states would have voted in favor of same-sex marriage last year, including the four states that actually did so.

The model also projects, however, that a national referendum to approve same-sex marriage would have narrowly failed last year, 48 percent to 52 percent, despite national polls showing more voters approving same-sex marriage than opposing it. For right now, it is probably best to treat the question of whether a majority of Americans support same-sex marriage as having an ambiguous answer. Polls are on the verge of saying that they do, but the ballot results are more equivocal.

By 2016, however, voters in 32 states would be willing to vote in support of same-sex marriage, according to the model. And by 2020, voters in 44 states would do so, assuming that same-sex marriage continues to gain support at roughly its previous rate.

Thus, even if one prudently assumes that support for same-sex marriage is increasing at a linear rather than accelerated pace, and that same-sex marriage will not perform quite as well at the ballot booth as in national polls of all adults, the steady increase in support is soon likely to outweigh all other factors. In fact, even if the Supreme Court decision or some other contingency freezes opinion among current voters, support for same-sex marriage would continue to increase based on generational turnover, probably enough that it would narrowly win a national ballot referendum by 2016. It might require a religious revival among the youngest generation of Americans to reverse the trend.

“Maine is a relatively old state and a rural one, which may account for why it initially rejected same-sex marriage in 2009 despite being liberal and irreligious.”

Or maybe it has more to do with money, lies, and political organization?

1 comment

  1. ek hornbeck

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