THE LABORATORIES WERE SENT THREE SOIL SAMPLES. SAMPLE A FROM A BURGLARY SCENE, AND SAMPLE B AND C FROM THE SHOES OF TWO DIFFERENT SUSPECTS. THE LABORATORIES WERE TO DETERMINE WHETHER B AND/OR C COULD HAVE COME FROM THE SAME SOURCE AS A AND TO INDICATE THEIR METHODS OF ANALYSIS. IN REALITY, NEITHER B NOR C CAME FROM THE SAME SOURCE AS A. OF THE RESPONDING LABORATORIES, 25 (28.4 PERCENT) CONCLUDED THAT BOTH B AND C COULD HAVE COME FROM THE SAME SOURCE AS A; 2 (2.2 PERCENT) CONCLUDED THAT B BUT NOT C COULD HAVE COME FROM THE SAME SOURCE AS A; AND 55 (62.5 PERCENT) CONCLUDED THAT NEITHER B NOR C COULD HAVE COME FROM THE SAME SOURCE AS A. DETAILS OF THE LABORATORIES' FINDINGS AND METHODS ARE PRESENTED IN EIGHT TABLES, TOGETHER WITH DATA ON THE SAMPLE SUPPLIER'S CHARACTERIZATION OF THE SAMPLES AND THE FINDINGS OF THREE REFEREE LABORATORIES. BREAKDOWNS OF RESPONSES FROM INDIVIDUAL LABORATORIES ARE INCLUDED. INFORMATION ON SURVEY METHODS AND A COPY OF THE SURVEY INSTRUMENT ARE PROVIDED. OTHER PROFICIENCY TESTS ARE DOCUMENTED IN NCJ 47522-47531 AND 47533-47542. (LKM)