This, between Brendan Nyhan and Politico reporter Alex Burns is worth reading as another chapter in the vexed relationship between political science and horserace journalism. The underlying disagreement here is over which kinds of knowledge count. On the one hand, Burns suggests that the collective wisdom among well-connected DC politicians is strong evidence of what is actually true in national politics. On the other, Nyhan wants polling data or similar. What’s interesting is that this conversation wouldn’t have been likely to have happened a few years ago. Someone in Burns’ position would not have felt obliged to defend their form of specialized knowledge a few years ago, because it would have seemed self-evidently unassailable. The rise of an alternative set of norms about which knowledge is appropriate to settling this kind of dispute, appealing to very different kinds of evidence is an important sociological change in journalism (which has perhaps been pushed on a little by blogs like ours, but which is probably more directly driven by an increased willingness of prominent journalists to engage directly with data, efforts to figure out which causal relationships are plausible, which implausible and so on).
[updated to bring the underlying argument out better]