I just stumbled across someone from the Conference Board of Canada making some comments. I often wonder at the quality of the analysis that comes out of think tanks. Typically, it's very opaque, designed so that only the executive summary needs to be read, and the details of the actual nuts and bolts are often nowhere to be found. (I have no comment on this particular study.)
I do speak from experience, to some degree. A lot of studies came through our group, and people with backgrounds in political science, sociology, english, etc, were picking these things apart on the basis of their technical merits. It was, at times, like shooting fish in a barrel.
C.D. Howe is often pretty good, but aside from that, nothing really comes to mind. Many, many grains of salt.
UPDATE: Here's one particularly egregious example.