THE RESEARCHERS TOOK ADVANTAGE OF A CHANGE IN THE POLICY OF THE PROSECUTOR'S OFFICE IN KING COUNTY, WASH., WHICH INVOLVED AN INCREASE IN THE NUMBER OF PROSECUTIONS OF UNLICENSED CONTRACTORS OVER A PERIOD OF 3 TO 4 YEARS, TO CONDUCT A QUASI-EXPERIMENTAL STUDY OF THE DETERRENT EFFECT OF THE NEW POLICY. THE STUDY TREATED PROSECUTOR ACTIVITY AS AN INTERVENTION EXPECTED TO REDUCE THE NUMBER OF HOME IMPROVEMENT FRAUD COMPLAINTS IN TWO OFFICES--THE SEATTLE DEPARTMENT OF CONSUMER AFFAIRS AND THE KING COUNTY BRANCH OF THE ATTORNEY GENERAL'S CONSUMER PROTECTION DIVISION. A BASELINE PERIOD OF LOW PROSECUTOR ACTIVITY WAS ESTABLISHED AND COMPARED WITH THREE SUBSEQUENT PERIODS WHERE A DECLINE IN COMPLAINTS OF HOME REPAIR FRAUD WAS EXPECTED TO OCCUR DUE TO INCREASED PROSECUTOR ACTIVITY. THESE PERIODS WERE MEASURED BY DUMMY VARIABLES INTRODUCED AS INTERACTION EFFECTS WITH TIME. THROUGH THE USE OF CONTINUOUS AND DUMMY VARIABLES IN A REGRESSION EQUATION, THE STUDY CONTROLLED FOR EXTERNAL EFFECTS ATTRIBUTED TO CHANGES IN DEMAND FOR HOME REPAIRS AND THE EFFECTS OF SHORT-TERM PUBLICITY ON COMPLAINTS. DATA FROM THE DEPARTMENT OF CONSUMER AFFAIRS SHOWED A TENDENCY TOWARD A DECREASE IN HOME REPAIR FRAUD AS A RESULT OF INCREASED CONVICTIONS. THE NEGATIVE RELATIONSHIP BETWEEN THE AMOUNT OF HOME REPAIR FRAUD AND GENERAL COMPLAINT LEVEL IN THE ATTORNEY GENERAL'S OFFICE SUGGESTS A CEILING ON THE NUMBER OF CASES THAT CAN BE RECEIVED. THE STUDY RESULTS SHOULD ENCOURAGE INCREASES IN PROSECUTION OF HOME REPAIR DEFRAUDERS, ALONG WITH INCREASES IN THE SEVERITY OF SANCTIONS. TABULAR DATA, NOTES, AND REFERENCES ARE PROVIDED. (RCB)