NCJ Number
63192
Journal
Police Journal Volume: 52 Issue: 4 Dated: (OCTOBER-DECEMBER 1979) Pages: 358-367
Date Published
1979
Length
10 pages
Annotation
THE ARGUMENT THAT THE CONCEPT OF ENTROPY SHOULD BE APPLIED AS A MEASURE OF POLICE SUCCESS INSTEAD OF CLEARANCE RATE STATISTICS IS PRESENTED; LOGICAL JUSTIFICATION OF ENTROPY USE IS EMPHASIZED.
Abstract
TRADITIONALLY, THE MEASURE USED TO INDICATE POLICE EFFECTIVENESS IS THE CLEARANCE OR DETECTION RATE, DEFINED AS THE PROPORTION OF CRIMES KNOWN TO THE POLICE THAT ARE SOLVED. THE CLEARANCE RATE HAS MANY ADVANTAGES IN THAT IT IS EASY TO CALCULATE AND WOULD APPEAR TO BE A LOGICAL METHOD. NEVERTHELESS, IT HAS MANY INHERENT DISADVANTAGES AS A PERFORMANCE MEASURE. IT DOES NOT ALWAYS FOLLOW THAT A FORCE WITH A HIGHER CLEARANCE RATE IS NECESSARILY MORE EFFICIENT THAN A FORCE WITH A LOWER RATE. FOR EXAMPLE, IF THE REMAINS OF A BODY ARE FOUND IN AN ISOLATED FIELD SEVERAL YEARS AFTER DEATH HAS OCCURRED, A THOROUGH, COMPETENT FORCE MIGHT DETERMINE THAT A HOMICIDE HAS BEEN COMMITTED, AND SO RECORD THE INCIDENT. IN ALL PROBABILITY, HOWEVER, THE CHANCES OF SOLVING THE CRIME ARE SLIM BECAUSE OF THE TIME FACTOR AND THE CRIME WOULD CARRY A NEGATIVE VALUE IN CLEARANCE RATE STATISTICS. A LESS EFFICIENT FORCE, FACED WITH SIMILAR CIRCUMSTANCES, MIGHT RULE THE DEATH ACCIDENTAL, AND THEREFORE WOULD NOT CARRY AN UNSOLVED MURDER ON ITS RECORDS. CLEARANCE RATES WOULD INDICATE THAT THE SECOND FORCE IS THE MORE EFFICIENT OF THE TWO, WHEN IN TRUTH IT IS NOT. UNFORTUNATELY, THE GREATER THE EMPHASIS ON CLEARANCE RATES, THE GREATER THE TEMPTATION BECOMES FOR POLICEMEN TO PUT PAPER SUCCESS BEFORE TRUE SUCCESS. THE APPLICATION OF THE ENTROPY CONCEPT WOULD RESOLVE THIS CONFLICT. ENTROPY, FIRST USED IN THERMO-DYNAMICS, MEASURES THE DEGREE OF CHOICE OR UNCERTAINTY WHICH EXISTS IN A SITUATION. IT IS EXPRESSED IN TERMS OF THE PROBABILITIES INVOLVED. TO ESTABLISH THE TRUTH, THE POLICE NEED INFORMATION. INFORMATION CAN BE OF VALUE TO THE POLICE EITHER BY REDUCING THE UNCERTAINTY ASSOCIATED WITH THE AMOUNT OF CRIME IN THE AREA, OR BY DECREASING THE UNCERTAINTY RELATING TO THE CULPRIT. FOR UNSOLVED CRIMES A RESIDUAL UNCERTAINTY REMAINS. FAR FROM PENALIZING THOSE FORCES WHICH RECORD THOSE CRIMES WHICH HAVE LITTLE CHANCE OF BEING SOLVED, THE MEASURE OF THE LEVEL OF RESIDUAL UNCERTAINTY INDICATES AN INCREASE IN POLICE PERFORMANCE; THE INFORMATION THAT A CRIME HAS BEEN COMMITTED REDUCES THE UNCERTAINTY OF THE FIRST CRITERIA CATEGORY. RESULTS OBTAINED FROM A SIMULATION OF A POLICE AREA IMPLEMENTING THE METHOD WERE ENCOURAGING AND FURTHER EXPERIMENTS ARE SUGGESTED. REFERENCES, DATA, AND A FLOW CHART ARE INCLUDED IN THE ARTICLE. (LWM)