U.S. flag

An official website of the United States government, Department of Justice.

NCJRS Virtual Library

The Virtual Library houses over 235,000 criminal justice resources, including all known OJP works.
Click here to search the NCJRS Virtual Library

LABORATORY PROFICIENCY TESTING PROGRAM - SUPPLEMENTARY REPORT, SAMPLES 16-21

NCJ Number
48648
Author(s)
J L PETERSON; E FABRICANT
Date Published
1977
Length
44 pages
Annotation
THE FREQUENCY OF CORRECT AND INCORRECT RESPONSES BY FORENSIC LABORATORIES PARTICIPATING IN PROFICIENCY TEST ANALYSES OF PAINT, METAL, HAIR, WOOD, DOCUMENT, AND FIREARMS EVIDENCE IS DISCUSSED.
Abstract
THE REPORT IS INTENDED AS A SUPPLEMENT TO THE SEPARATE REPORTS DOCUMENTING PROFICIENCY TEST FINDINGS FOR EACH OF THE EVIDENCE SAMPLES DISTRIBUTED TO PARTICIPATING LABORATORIES. FOR EACH TYPE OF EVIDENCE, TEST PROCEDURES ARE SUMMARIZED, FINDINGS ARE REPORTED, AND CONCLUSIONS ARE DRAWN REGARDING THE ABILITY OF PARTICIPATING LABORATORIES TO CARRY OUT THE NECESSARY TESTS AND TO REPORT THEIR RESULTS. WITH REGARD TO PAINT ANALYSIS, SPECIAL ATTENTION IS DRAWN TO THE VARIATION AMONG LABORTORIES IN THE USE AND INTERPRETATION OF CHEMICAL SPOT TESTS AND SOLUBILITY TESTS. RELATIVELY FEW LABORATORIES HAD DIFFICULTY ANALYZING AND CHARACTERIZING METALS, BUT FEW LABORATORIES RESPONDED TO THE SURVEY INSTRUMENT'S REQUEST TO SUPPLY QUANTITATIVE DATA ON METAL SAMPLES. THE CONSIDERABLE MISIDENTIFICATION OF ANIMAL HAIR, PARTICULARLY DOG HAIR, IS SAID TO REFLECT CARELESSNESS OR LACK OF EXPERIENCE ON THE PART OF EXAMINERS AND INADEQUATE REFERENCE COLLECTIONS OF STANDARD HAIRS. THE NUMBER OF MISIDENTIFICATIONS OF WOOD SAMPLES IS SAID TO BE INTOLERABLY HIGH AND IS ALSO ATTRIBUTED TO SHORTCOMINGS ON THE PART OF EXAMINERS AND TO INADEQUATE COLLECTIONS OF STANDARD SAMPLES. THE IMPORTANCE OF THE QUALITY, AS OPPOSED TO THE NUMBER OF YEARS, OF AN EXAMINER'S EXPERIENCE IS BROUGHT OUT WITH REGARD TO LABORATORY PERFORMANCE ON QUESTIONED DOCUMENT EXAMINATION. THE MISIDENTIFICATION OF PROJECTILES BY 5 OUT OF 88 LABORATORIES PARTICIPATING IN THE FIREARMS TEST IS REGARDED AS PARTICULARLY SERIOUS. TEST DOCUMENTS ARE APPENDED. FOR SUPPLEMENTARY REPORTS ON SAMPLES 1-15, SEE NCJ 41146-8. INDIVIDUAL TEST FINDINGS ARE REPORTED IN NCJ 47522-47542. SEE NCJ 48122 FOR THE FINAL REPORT OF THE TESTING PROGRAM. (LKM)