Realist evaluation methodology

Realist evaluations ask not, “What works?” or “Does this program work?” but ask instead, “What works for whom in what circumstances and in what respects, and how?” Realist evaluation embarks on this explanatory quest on the grounds that it is panacea phobic. Programs are products of the human imagination in negotiation. They never work indefinitely, in the same way, or in all circumstances, nor do they work for all..

In other words it is simple realistic about the success of any programme and attempts to be honest not only about the successes but also the failures of an intervention.  A white box approach to research.