EDIT - Upon further review, I have come to the conclusion that this is wrong.
http://papers.ssrn.com/sol3/papers.cfm?abstract_id=588453
http://www.cxoadvisory.com/blog/Default.asp
Accusations of political bias in the media are often made by members of both political parties, yet there have been few systematic studies of such bias to date. This paper develops an econometric technique to test for political bias in news reports that controls for the underlying character of the news reported. Our results suggest that American newspapers tend to give more positive news coverage to the same economic news when Democrats are in the Presidency than for Republicans. When all types of news are pooled into a single analysis, our results are highly significant. However, the results vary greatly depending upon which economic numbers are being reported. When GDP growth is reported, Republicans received between 16 and 24 percentage point fewer positive stories for the same economic numbers than Democrats. For durable goods for all newspapers, Republicans received between 15 and 25 percentage points fewer positive news stories than Democrats. For unemployment, the difference was between zero and 21 percentage points. Retail sales showed no difference. Among the Associated Press and the top 10 papers, the Washington Post, Chicago Tribune, Associated Press, and New York Times tend to be the least likely to report positive news during Republican administrations, while the Houston Chronicle slightly favors Republicans. Only one newspaper treated one Republican administration significantly more positively than the Clinton administration: the Los Angeles Times' headlines were most favorable to the Reagan administration, but it still favored Clinton over either Bush administration. We also find that the media coverage affects people's perceptions of the economy. Contrary to the typical impression that bad news sells, we find that good economic news generates more news coverage and that it is usually covered more prominently. We also present some evidence that media treats parties differently when they control both the presidency and the congress.
http://papers.ssrn.com/sol3/papers.cfm?abstract_id=588453
August 22, 2006 - A Republican Risk Premium?
Is the media more likely to accentuate the negative when Republicans hold the Presidency? In their October 2004 paper entitled "Is Newspaper Coverage of Economic Events Politically Biased?", John Lott Jr. and Kevin Hassett of the American Enterprise Institute test for political bias in the economic (durable goods, GDP, retail sales and unemployment) news coverage of American newspapers, after controlling for economic content. Using headlines from a database of newspaper and wire service articles from 389 newspapers covering January 1991 through May 2004 (and back to 1985 for the top ten newspapers: USA Today, Wall Street Journal, New York Times, Los Angeles Times, Washington Post, New York Daily News, New York Post, Chicago Tribune, Newsday and Houston Chronicle), they find that:
- American newspapers tend to report the same economic news more positively when Democrats hold the Presidency. No newspaper shows pro-Republican bias, and the large national newspapers all tend to slant headlines favorably for Democrats.
- Specifically, controlling for economic content, Republican presidents get 20-30% less positive coverage on average from all newspapers and 20-40% less positive coverage from the top ten papers than do Democrats.
- There is no evidence that this bias varies with a President’s approval rating.
- Media coverage relates positively to perceptions about the economy. Partisan bias produces a 7-9% difference in survey respondents viewing the economy as getting better.
- Contrary to popular belief, good economic news generates more coverage than bad news.
In summary, a pro-Democrat/anti-Republican bias in the mainstream media may affect the economic risk perception of some investors/potential investors, thereby affecting stock valuations.
This bias may reflexively offset any perception that Republicans are better for business (and therefore stocks) than are Democrats.
We wonder whether the migration to online news sources is affecting either the level or the impact of mainstream media bias.
For related research, see Blog Synthesis: Sentimental Journey, encompassing a broad range of equity market sentiment measures. See also our blog entry of 8/8/06, which examines whether the stock market does better under Democratic or Republican presidents.
http://www.cxoadvisory.com/blog/Default.asp