20 October 2008
How the Kohut Lacuna may help McCain
Just when even your friendly old Exile had begun to think that the American election was a done deal with Barrack Obama cruising towards the White House, the whole damned thing opened up again. The opinion polls show a narrowing of the gap between Obama and John McCain, with an average lead for the frontrunner now standing at a six percent average.
That sounds like a commanding lead until we remember that in the primaries Obama had an average eight percent lead over Hillary Clinton in places like New Hampshire and still managed to lose that race. The polls got it bang to rights for the Republican primaries, but throughout the primary elections they managed to overestimate Barrack Obama's level of support.
There are two issues that tell against Obama. The first is the Bradley Effect which we have discussed in an earlier posting, but to summarise here, involves white people lying to the pollsters about which candidate they intend to vote for.
The second factor is what is known as the Kohut Lacuna and is named after Andrew Kohut, the head of the Pew Research Centre who came up with the idea back in January of this year. A lacuna is just the Latin word for a gap, and the Kohut Lacuna is summed up best in the man's own words:
Poorer, less well-educated white people refuse surveys more often than affluent, better-educated whites. Polls generally adjust their samples for this tendency. But here’s the problem: these whites who do not respond to surveys tend to have more unfavorable views of blacks than respondents who do the interviews.So this is different from the Bradley Effect which involves out and out lying about one's voting intentions, but it is closely related to it in its outcome. Thanks to both of them the polls overestimate the level of support that Obama actually has.
As Obama's lead narrows then both Bradley and Kohut may come into play. Obama led by eight percent in New Hampshire and still lost that election. Given that his lead is now just six percent the same thing could quite conceivably happen again.