Crime laboratory proficiency testing results, 1978-1991, I: Identification and classification of physical evidence.

The proficiency testing of crime laboratories began in the mid-1970s and presently assumes an important role in quality assurance programs within most forensic laboratories. This article reviews the origins and early results of this testing program and also examines the progress of proficiency testing in allied scientific fields. Beginning in 1978, a fee-based crime laboratory proficiency testing program was launched and has grown to its present level involving almost 400 laboratories worldwide. This is the first of two articles that review the objectives, limitations and results of this testing from 1978 through 1991. Part I reviews the success of laboratories in the identification and classification of common evidence types: controlled substances, flammables, explosives, fibers, bloodstains, and hairs. Laboratories enjoy a high degree of success in identifying drugs and classifying (typing) bloodstains. They are moderately successful in identifying flammables, explosives, and fibers. Animal hair identification and human hair body location results are troublesome. The second paper will review the proficiency of crime laboratories in determining if two or more evidentiary samples shared a common origin.