[G]overnment bureaucracies non-self-evaluate. At a minimum, agencies with evaluative responsibilities are not invited to evaluate - they are kept out of the loop, their opinions unsought. At a maximum,government agencies actively suppress their own internal evaluative units and are discouraged from evaluating the beliefs and policies of other agencies.
The quote is from Why states believe foolish ideas by Steven van Evera, which is well worth reading in full. We need to be reminded that around 40 per cent of the rich world's income is spent by organisations that resist, almost to the death, the idea of examining their policy blunders and learning from them. I mean, of course, governments. Van Evera says that even in the world wars of the 20th century, when policy mistakes could have grievous consequences: 'the belligerents made large errors without carefully assessing their options. Even rudimentary analysis often would have exposed these errors but was omitted.'
In my limited experience, it is often the smallest decisions in government that receive most scrutiny: whom to offer a three-month contract; which brand of computer printer to buy; that sort of thing. The larger decisions often escape detailed analysis. Sometimes this is unavoidable but what is inexcusable is that lessons from policymaking disasters are never learned. It's now estimated that the war in Iraq will cost the US about 10 times more than the White House projected. This calculation was done by a non-governmental body and it's a safe bet that it will never be referred to when similar enterprises are considered in the future.