In this updated analysis, Silver works to predict the likelihood that various US states will approve bans on same-sex marriage and civil unions. Using data from the 2008 National Annenberg Election Study (yay Anneberg!), Silver incorporates three key state-level variables: median age, ideological orientation (balance between liberals and conservatives), and religiosity. Silver is correct to incorporate these three considerations -- previous research (my own work included) shows strong and significant negative relationships between conservative political ideology, religiosity, age, and opinions toward same-sex marriage.
Also included are two time-trend or time series variables that measure different approaches to changing public opinion on the issue: a linear trend and an accelerated trend that is set-up to match national shifts in public opinion on the issue. Time-trend or time series variables simply measure change in opinion over time.
According to Silver, here are the results:
"The most generous set of assumptions for gay rights advocates are that the ballot initiatives would seek to ban civil unions in addition to same-sex marriage, and that the Accelerated Model most accurately reflects current sentiment about marriage. Under these assumptions, all but 15 states would be projected to reject such a ballot initiative if one were on the ticket next year.
The most restrictive assumptions, by contrast, are that the ballot initiatives would single out marriage only, and that the Linear Model is correct. Under these rules, all but 14 states (and the District of Columbia) would be projected to find a majority for a ban on same-sex marriage."
Well first as Silver correctly points out, there is a fair amount of noise in his models -- or more precisely, the margin of error is rather high -- we're talking +/- 8 points. Here's another way to think about margin of error. In the 2008 election, Barack Obama received 53% of the popular vote to McCain's 46%. A margin of error of 8 points would mean a range for Barack Obama of between 45-61% and a range for McCain of 38-54%. That's a big overlap.
What does this mean?
What does this mean?
While Silver's model offers some interesting analysis, the bottom line is that there is still more work to be done in order to more precisely predict how states beyond New York will evaluate same-sex marriage and civil unions ballot measures.
"In short, the future for same-sex marriage looks to be reasonably bright. Most of the states that were fertile ground for passing a constitutional ban on it did so long ago. Minnesota and North Carolina are potential exceptions, but the six states that have gender-neutral marriage laws on the books now are unlikely to see them reversed, while some of those that don’t are in a position for gay rights advocates to go on offense."
Just how bright a future, remains to be seen. Look for a range of states to consider the issue in 2012 and beyond.