THE LABORATORIES WERE SENT THREE FIBER SAMPLES, TOGETHER WITH THE INDICATION THAT SAMPLE C REPRESENTED FIBERS FOUND AT THE SCENE OF A HOMICIDE AND THAT SAMPLES A AND B WERE FROM THE SHOES OF TWO SUSPECTS. THE LABORATORIES WERE TO DETERMINE WHETHER A AND/OR B COULD HAVE COME FROM THE SAME SOURCE AS C AND TO INDICATE THEIR METHODS OF ANALYSIS. IN REALITY, NEITHER A NOR B WAS THE SAME AS C. OF THE RESPONDING LABORATORIES, 114 (98.3 PERCENT) DETERMINED CORRECTLY THAT NEITHER A NOR B WAS THE SAME AS C. DETAILS OF THE LABORATORIES' METHODS AND FINDINGS, TOGETHER WITH THE SAMPLE SUPPLIER'S CHARACTERIZATION OF THE SAMPLES AND THE FINDINGS OF REFEREE LABORATORIES, ARE PRESENTED IN EIGHT LABORATORIES ARE INCLUDED. AN EXPLANATION OF SURVEY METHODS AND A COPY OF THE QUESTIONNAIRE ARE PROVIDED. PROFICIENCY TESTS INVOLVING OTHER ITEMS OF PHYSICAL EVIDENCE ARE REPORTED IN NCJ 47522-47532 AND 47534-47542. (LKM)