The Huffington Post recently reported that the popular Gallup poll surveys often survey a disproportionate amount of blacks and Hispanics, thus negatively affecting President Barack Obama‘s poll numbers. A look at a recent USA Today/Gallup poll showed that the polling agencies only surveyed 21.4 percent of ‘non-whites’ compared to the actual population percentage of 25.5 percent. The Huffington Post has more:
Over the weekend, The Huffington Post ran an in-depth analysis of the way the Gallup Poll handles race in its survey samples. (Go read it if you haven’t yet.) Now, Jay Cost at The Weekly Standardhas taken me to task, particularly for “looking at Gallup in isolation.” But Cost misses the main point of the article.
Cost says my “bottom line” is that Gallup “tends to place the president’s job approval rating about 2.5 points below the average of similar polls, and that a portion of this can be chalked up to under-sampling non-whites.”
All pollsters, not just Gallup, typically under-sample non-whites in their raw data. My bottom line is that when Gallup weights those samples to account for the under-sampling, it still under-represents non-whites in its weighted data. The U.S. Census Bureau’s Current Population Survey (CPS), the benchmark that Gallup uses to weight its samples, finds that 25.5 percent of American adults describe themselves as Hispanic or black alone (without offering another race). Yet in the results of the seven USA Today/Gallup surveys conducted from January to March 2012 that I examined, the combined percentage of adults who were Hispanic or black alone was just 21.4, a difference of 4.1 percentage points.
Click here for the full story.