"Sources of Media Bias"
Tyler Cowen observes:
I might add that Washington Post restaurant reviews are far too positive. If WP readers were simply told “There are hardly any good restaurants in your crummy little city,” this wouldn’t do much for WP circulation or advertising revenue.
This sort of thing — the need to keep running a business — is the real source of media bias in all domains. Note that it also wouldn’t work to say “there are a bunch of good restaurants in your city, but nothing much has changed in the past 18 months.” Note similarly that things like People‘s “50 sexiest people” list have implausible levels of turnover. Sometimes this sort of thing can have really pernicious effects, like US News‘s college rankings which aren’t taken seriously by anyone who understands the issues but seem to have a large distorting effect on the policies of many American colleges and universities.