Econometricians are often pretty smart at thinking up ways to measure things. I recently attended a seminar by Professor Matthew Gentzkow from University of Chicago Graduate School of Business who is doing research on the vexed issue of media slant. You might think that media slant or media bias is completely in the eye of the beholder. There is no âfair mediaâ to anchor against I hear you cry. But economists have no need of such notions as fairness. They look for comparisons, differences. And their anchor is âwhat would a rational utility maximiser do?â The bottom line ends up being : âIf it looks like a goat and sounds like a goat, its probably a goatâ.
For those of you who have limited time to read the paper, my executive summary is below.
First, you can measure newspaper bias in a natural and objective manner – natural because the final measure has a simple and natural interpretation, objective because it is done by a computer not a person. The idea is to build a text processing algorithm whose aim it to to classify members of congress as republican or democrat on the basis of their use of certain phrases in their recorded utterances in the house. For instance, what republicans might call the War on Terror, democrats will call the War in Iraq. You then apply the same algorithm to the news text* of newspapers. And you end up with a measure such as âif the SMH were a member of parliament it would be 71% likely to be an ALP member.â Gentzkow and Shapiro have done this for a wide range of US papers. Pretty damned clever, heh?
Second, are papers across the nation collectively biased? Both left and right have argued that they are (in opposite directions of course). Well, it turns out that collectively they are slightly left leaning, in the sense that the US newspapers collectively have an average slant that corresponds to a 47% republican complexion whereas during the period of evaluation republican support was around 53%.
Third, is this bias politically driven, for instance by the reporters? Economists would like to explain actions in terms of utility maximization. And newspapers are for-profit businesses so their utility has a lot to do with profit which means sales. If we start with the idea that left/right readers like to read left/right papers and if the left are better educated and read more, then the slight left leaning bias could just be a rational market response by the newspapers. The authors look at the relationship between slant of papers and the political leanings of their geographical catchment area and find that there is a clear relationship. Further, they estimate that if newspapers were rationally maximizing profit within each catchment then the average political slant should turn out to be equivalent to a 46% republican complexion. And the papers are slightly to the right of this profit maximizing point.
Finally, do owners of papers impose slant? Statistically, we would ask whether the variation in slant from newspaper to newspaper can be explained by ownership. It appears not from the data. You do not get a better predictor of slant by including ownership in the regression, and there does not seem to be significant correlation within stables of papers with a common owner, after other things like geography are taken into account.
I would love to have the time to do a similar study in Australia. My perception is that the Oz is blatantly biased on the issue of workchoices and the SMH is blatantly biased on any issue around social progressiveness. But the bias is just as likely to be within my own skull.
* The algorithm is only run on news text, not opinion pieces or editorials. One may argue that bias in these is less important since it is overt.