Click to enlarge.
Ireland made history last Friday, approving an amendment that enshrined marriage equality in the country's constitution by a wide 62-38 margin. As you can see in the map above, the "yes" vote carried a majority in all except one constituency, and passage of the referendum made Ireland the first country in the world to ensure marriage equality by popular vote. A bill to allow same-sex marriages is expected to be enacted by the end of July, and marriages would follow in early autumn.
Many news reports mentioned the high turnout for the vote, especially among young people. We explore that topic below the fold.
It turns out that turnout was not uniformly high. It varied from around 50 to 70 percent, and there was only a weak correlation between turnout and support for the referendum, as seen in the chart on the left. However, if we use turnout from the 2011 Irish general election as a baseline for comparison, we see a strong relationship. (The x-axis of the chart on the right shows 2015 turnout as a percentage of 2011 turnout.) Indeed, in the areas most supportive of marriage equality (Dublin), turnout was nearly equal to that of the 2011 general election.
Although we can't tell from these data exactly what the difference in turnout was between supporters and opponents of marriage equality, it's clear that communities with stronger support for marriage equality were more likely to turn out at greater rates. In other words, it just may be that if you give people something to vote for, they'll vote.