Demography and irreligion, one year on

by John Quiggin on August 1, 2016

Almost exactly a year ago, I posted about a Pew study predicting that the proportion of the world population without a religious affiliation would decline sharply by 2050. The basic argument sounds plausible: an increase in the unaffiliated proportion of the population within countries will be more than offset by faster population growth in countries with higher rates of affiliation. But a closer look revealed a surprising prediction for the US, the projection that Christians would decline from 78.3 per cent of the US population in 2010 to 66.4 per cent in 2050 (emphasis added), while the unaffiliated would rise from 16 to 26 per cent. Given that more than 30 per cent of Millennials are already unaffiliated, that seemed like a surprisingly slow rate of change. However, judging by the comments threads, a lot of readers seemed to find the Pew projections fairly plausible.

A year on, Pew has undertaken a new survey focused on the US election. The headline results are for registered voters, but the results turn out to be the same as for the full sample. The big news: “The non-religious are now the country’s largest religious voting bloc, at 21 per cent of registered voters. The Christian groups reported by Pew add up to 66.7 per cent of the population (my calculation, and emphasis added). Other religions account for 11 per cent (according to the WP) leaving a small residual (maybe “declined to say”).

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