ABSTRACT
The concept of evidence, largely neglected by researchers in the social sciences for many years, has recently become a hotly contested one, largely because of the rise of movements for "evidence-based" practice and policy. Much of the critique of the evidence-based movement by qualitative researchers has been based on a social constructivist or postmodern epistemology that challenges the basic concept of "evidence". This has also been true of the larger debate over evidence in the social sciences, and has "threatened to reduce the role of evidence, facts, and proof to the point of nonexistence". Achinstein draws a number of other conclusions from this claim-dependence and context-dependence of evidence. A particular piece of data might by itself be evidence for a claim, but not when considered in combination with other evidence. Evidence is therefore an interpretation of the data or observations, and "evidence" is an essentially contested concept.
