think on this.

Of the six studies that Gov Romney cites to defend his mathematically-challenged tax plan, a few were blogs and were thus often dismissed by critics as being de facto inadequate evidence simply by dint of being blog posts. As an active, evidence-based blogger, I can only say…quelle horreur! Actually, I think it’s entirely fair to heavily discount blogs as evidence. Obviously, quality varies widely and there are no gate keepers on the net, and nothing approaching rigorous peer review. However, there’s room for nuance. First, some blogs, like the ones at CBPP and EPI (not to leave anyone out, but those are places I’ve worked so I know how they operate), generally report shortened, reader-friendlier versions of their studies, so judging those blogs as evidence depends on your view of their studies. Which gets to my larger point—I wouldn’t generally trust blogs as evidence but neither would I trust every think tank report. The most reliable basis for trustworthy evidence in social science is peer review, a process by which experts of the established knowledge on the topic, along with rigorous application of the rules of statistical evidence, evaluate the claims in the study before it can be published. …

The thing I’ve always found useful about the work of the think tanks I trust is that they tend to take a pretty-much “just the facts ma’am” approach in their reporting.  CBPP and EPI reports, for example—again, places I cite because I know first hand how they make the sausage—tend to be based on data series from established data sources with little manipulation.  They offer interpretation, but the facts and data processes are right out there and derived from trustworthy source material. … But blogs are by nature quick, impressionistic takes on issues.  They can point you in the direction of deeper dives, but they will very rarely, I think, provide adequate evidence for policy decisions.