THE TEST ANALYSES WERE PART OF A LABORATORY PROFICIENCY TESTING PROJECT. EACH LABORATORY RECEIVED THREE SAMPLES OF GLASS, TOGETHER WITH THE INDICATION THAT SAMPLES A SEND B HAD BEEN REMOVED FROM THE CLOTHING OF TWO HIT AND RUN VICTIMS FOUND AT DIFFERENT LOCATIONS AND THAT SAMPLE C HAD BEEN REMOVED FROM A SUSPECT VEHICLE. THE LABORATORIES WERE TO DETERMINE WHETHER SAMPLE A AND/OR B COULD HAVE A COMMON ORIGIN WITH SAMPLE C. THE LABORATORIES WERE ALSO ASKED TO INDICATE THEIR METHODS OF ANALYSIS. IN REALITY, THE THREE SAMPLES ALL HAD BEEN PREPARED FROM THE SAME HEADLIGHT. OF THE 112 RESPONDING LABORATORIES, 77.7 PERCENT REPORTED THAT B AND C WERE THE SAME, BUT ONLY 68.8 PERCENT REPORTED THAT BOTH A AND B WERE THE SAME AS C. TABULAR DATA ON LABORATORY FINDINGS AND METHODS OF ANALYSIS -INCLUDING BREAKDOWNS OF THE RESPONSES OF INDIVIDUAL LABORATORIES -- ARE PRESENTED. AN EXPLANATION OF SURVEY METHODS AND A COPY OF THE QUESTIONNAIRE ARE INCLUDED. ANOTHER PROFICIENCY TEST INVOLVING GLASS ANALYSIS IS REPORTED IN NCJ-47525. OTHER PROFICIENCY TESTS INVOLVING OTHER FORMS OF PHYSICAL EVIDENCE ARE REPORTED IN NCJ 47522-47524, 47526-47529, AND 47531-47542. (LKM)