Most education research is unreliable

I've been reading through the archives at D-Ed Reckoning, a blog with lots of good discussion about education policy and research. This post makes the point that not all research is equal and provides a basic checklist a layman can use to spot a poorly designed study. Unfortunately, concludes the author,

There is very little education research (and subsequent advocacy) that meets all these criteria. Typically, when any serious meta-analysis of education research is conducted, about 90% of it has to be discarded as lacking. Journalists and edu-bloggers should be very leery relying on shaking [sic] education research.