A contribution to the discussion of probabilities and human hair comparisons

The paper by Gaudette and Keeping on "An Attempt at Determining Probabilities in Human Scalp Hair Comparison" in the Journal of Forensic Sciences (Vol. 19, No. 3, July 1974, pp. 599-606) has provoked considerable controversy. This paper highlights two of the sources of the controversy and shows how the probability, 1/4500, quoted by Gaudette and Keeping should be treated with caution. The necessity of the use of a likelihood ratio statistic is described. It is suggested that the hair examination form resulting from the responses to the questionnaire recently distributed by the authors and also the discussions at Quantico (Proceedings of the International Symposium on Forensic Hair Comparisons, 25-27 June 1985, Quantico VA) should be used to facilitate the collection of the data which will be necessary to enable a likelihood ratio statistic to be estimated effectively.     

"False confessions" and identification with the aggressor: another forensic misuse of a psychiatric concept

Some psychiatrists misuse theoretical concepts beyond their generally accepted dimensions in an attempt to support a conclusion favorable to a litigant or defendant. In the case presented, the concept of identification with the aggressor was used in an attempt to eliminate or minimize the effect of a confession and to buttress the claim that the confession itself was false. Quotations from the actual reports and testimony are used to reflect both this tactic and the context in which these issues were pursued, including a rather startling admission by the psychiatrist dealing with the thoroughness of his professional effort. A brief history of "identification with the aggressor" is presented, a history which contrasts with its application to rather routine police questioning. Similarly, skepticism is clearly merited when a psychitrist testifies as to truthfulness or falsity of a statement.