Blind tests in microscopic residue analysis: comments on Wadley et al. (2004)

In this comment, we critique a recent paper by Wadley, Lombard and Williamson entitled ‘The first residue analysis blind tests: results and lessons learnt’ (Journal of Archaeological Science 31 (2004) 1491–1501) as a means of assessing the role and utility of such blind tests. We find that apart from not being the first residue analysis blind tests, the tests conducted by Wadley et al. exhibit problems at each stage of experimental design. Most of the issues identified can be attributed to loss of experimental control, including lack of documentation of residues prior to blind testing and contamination of their samples. We suggest possible means of avoiding these issues in future microscopic residue analysis blind tests.