EACH LABORATORY WAS SENT THREE PAINT SAMPLES -- SAMPLE B REPRESENTING PAINT REMOVED FROM THE DOOR JAMB OF A BURGLARIZED BUILDING, AND SAMPLES A AND C FOUND ON THE CLOTHING OF TWO DIFFERENT SUSPECTS. THE LABORATORIES WERE TO DETERMINE WHETHER EITHER A AND/OR C COULD HAVE COME FROM THE SAME SOURCE AS B AND TO INDICATE THEIR METHODS OF ANALYSIS. THE SAMPLE SUPPLIER'S CHARACTERIZATION OF THE SAMPLES INDICATES THAT NONE COULD HAVE A COMMON ORIGIN WITH ANOTHER. A REFEREE LABORATORY'S FINDINGS CONFIRM THIS CHARACTERIZATION. OF THE RESPONDING LABORATORIES, 67 (65.6 PERCENT) CORRECTLY DETERMINED THAT NEITHER A NOR C WAS THE SAME AS B; 11 (10.7 PERCENT) RESPONDED THAT A BUT NOT C WAS THE SAME AS B; 11 (10.7 PERCENT) RESPONDED THAT C BUT NOT A WAS THE SAME AS B; 3 (2.9 PERCENT) ANSWERED THAT BOTH A AND C COULD HAVE COME FROM THE SAME SOURCE AS B; AND THE REMAINING 10 LABORATORIES REPORTED MIXED AND/OR INCONCLUSIVE FINDINGS. DETAILS OF THE METHODS AND FINDINGS ARE PRESENTED IN TABLES, INCLUDING A DETAILED BREAKDOWN OF RESPONSE FROM INDIVIDUAL LABORATORIES. AN EXPLANATION OF SURVEY METHODS AND A COPY OF THE QUESTIONNAIRE ARE PROVIDED. OTHER PROFICIENCY TESTS INVOLVING PAINT ANALYSIS ARE REPORTED IN NCJ-47526 AND 47531. TESTS OF OTHER SUBSTANCES ARE REPORTED IN NCJ 47522-47525, 47527-47530, 47532-47536, AND 47538-47542. (LKM)