Andrew Gelman and John Sides write about partisan bias in assessing economic conditions:
A good example comes from the research of Larry Bartels. He analyzed a 1988 survey that asked “Would you say that compared to 1980, inflation has gotten better, stayed about the same, or gotten worse?” Amazingly, over half of the self-identified strong Democrats in the survey said that inflation had gotten worse and only 8% thought it had gotten much better, even though the actual inflation rate dropped from 13% to 4% during Reagan’s eight years in office. Republicans were similarly biased about the Clinton-era economy: in 1996, a majority of Republicans thought that the budget deficit had increased. This partisan filter was also evident after the Democrats’ retaking of Congress in 2006. Research by Alan Gerber and Greg Huber shows that Democrats became much more optimistic, and Republicans more pessimistic, about the national economy.
As Ezra Klein pointed out some time ago, Bartels’ research actually suggests that the problem has odd interactions with levels of political information:
For one thing, the gap grows as levels of political information grow. But more interesting is that along most of the hierarchy, Republicans show the pattern you would assume — the more they knew, the more accurate their perceptions about the state of the budget deficit. But among very high-information Republicans, perceptions start getting less accurate. This is presumably because very high information Republicans were able to familiarize themselves with sophisticated arguments about why the apparent improvement wasn’t real improvement.
I assume the way this works is akin to how I was slower than most Americans to recognize that violence in Iraq was dipping not despite being better-informed about the situation in Iraq than most people but precisely because I was well-informed. Well-informed and suspicious! So I was keenly aware of all kinds of problems in the data and its presentation that undermined the dominant — and, it turns out, correct — narrative about an improving security situation.