http://www.nytimes.com/2012/04/01/opinion/sunday/the-social-sciences-physics-... Ten years after the publication of Scientific Research in Education, we in the social sciences continue to struggle with expectations that social science should be as certain, in both method and results, as natural science. Social science is so variable and unpredictable (because people are variable and unpredictable) that it deserves different methods, methods that wouldn't make much sense in natural science. It reminds me of this quote from David Berliner: "But the important distinction is really not between the hard and the easy sciences. Easy-to-do science is what those in physics, chemistry, geology, and some other fields do. Hard-to-do science is what the social scientists do and, in particular, it is what we educational researchers do. In my estimation, we have the hardest-to-do science of them all! We do our science under conditions that physical scientists find intolerable." Berliner, D. C. (2002). Educational research: The hardest science of all. Educational Researcher, 31(8), 18-20.