Previous posts have discussed the composition of the 2012 electorate. At the Pew Research Center, Paul Taylor and Mark Hugo Lopez write:
The Census Bureau made big news last week when it reported that the black voter turnout rate (66.2%) exceeded the white voter turnout rate (64.1%) for the first time ever in 2012. But a closer look at the numbers raises some intriguing questions.
It’s possible that the lines may have first crossed in 2008. But it’s also possible they may not have crossed at all.
Let’s start with the second scenario. It’s based on data that suggest that last year, blacks may have been more inclined than whites to report that they voted when in fact they didn’t. This is known as a “social desirability bias,” a familiar concern among survey researchers.
The Census Bureau bases its estimates of voter turnout on self-reports from a survey of a nationally representative sample of about 55,000 households. The survey is conducted in the two weeks after each federal election and is considered the best source of information on the demographics of the nation’s electorate. However, this self-report method typically produces a modest over-estimate of turnout, and 2012 was no exception. According to the Census Bureau’s estimates, 133 million Americans voted last year, but according to the official state-by-state tallies, just 129 million did.
Moreover, if you analyze the discrepancies by state, as the Pew Research Center has (download our Election Turnout Rates by State data in Excel), you find a pattern that casts some doubt on the Census Bureau’s announcement. It turns out that the phenomenon of over reporting tended to be most pronounced in states that have the highest share of blacks in their citizen-age electorate.