And how does a lack of even rudimentary knowledge of a specific field of study qualify one to reject it wholesale?<p>The difficulties in meta-analysis in the social sciences vary from field to field -- psychology is qualitatively different from anthropology or history -- but if we had to generalize, they have more to do with the sheer dimensionality of the problem combined with the difficulty of precise measurement (and sometimes obtaining a large-enough sample), than with the field being &quot;opinion based&quot; or the existence of &quot;mutually exclusive schools of thought&quot; (I don&#x27;t know how this differs from many other, more tractable research areas, and I don&#x27;t see how this can be reconciled with saying that there&#x27;s too much consensus).