But if you simply average all the data that post-dates the unveiling of Mr. Ryan as Mr. Romney’s running mate, we’re getting largely the same story that we did on Tuesday. Mr. Romney has gained a net of one point, on average, in the eleven polls conducted wholly or partially after his announcement of Mr. Ryan, compared to the prior renditions of the same surveys in the same states. This is a below-average “bounce” for the selection of a vice presidential candidate; in past elections, the bounce has averaged in the neighborhood of 4 percentage points instead.
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However, considering that the polls coincided with the announcement of Mr. Ryan, and that Purple Strategies polls have been a bit Republican-leaning so far this cycle (by an average of 2 points relative to the consensus), they aren’t quite as interesting.