INTERJURISDICTIONAL SPILLOVERS OF URBAN POLICE SERVICES

• NCJ Number: 54547
• Journal: Southern Economic Journal Volume: 43 Issue: 3 Dated: (JANUARY 1977) Pages: 1352-1359
• Author(s): S L MEHAY
• Date Published: 1977
• Length: 8 pages
• Corporate Author: Public Finance
• Publication Format: Document
• Publication Type: Report (Study/Research)
• Language: English
• Country: United States of America

Annotation

MATHEMATICAL EQUATIONS ARE DEVELOPED AND TESTED FOR A MODEL TO MEASURE CRIME SPILLOVER INTO ADJACENT COMMUNITIES WHEN LAW ENFORCEMENT MEASURES ARE IMPROVED IN A GIVEN POLICE JURISDICTION.

Abstract

THE MODEL ASSUMES THAT AN EQUILIBRIUM INPUT RATIO EXISTS BETWEEN ANY GIVEN CITY AND ITS RELEVANT NEIGHBORS AND THAT ANY DIVERGENCE CREATES CRIME DISPLACEMENT. A SECOND ASSUMPTION IS THAT THE STATIC SITUATION CAN BEST BE APPROXIMATED BY THE ABSOLUTE INPUT DIFFERENTIAL BETWEEN ADJACENT CITIES, ADJUSTED BY POPULATION. HENCE, THE STATIC DISEQUILIBRIUM LEVEL WILL REVEAL SPILLOVER FLOWS FROM CITIES WITH RELATIVELY HIGH PER CAPITA ENFORCEMENT INPUTS TO THOSE CITIES AMONG THEIR NEIGHBORS WITH RELATIVELY LOW PER CAPITA INPUT LEVELS, AS A CITY WITH A LOW PER CAPITA INPUT IS ASSUMED TO HAVE A CORRESPONDINGLY INFERIOR ENFORCEMENT LEVEL. THE SAMPLE USED TO TEST THE EQUATION INLCUDED 46 CITIES IN THE LOS ANGELES, CALIF., METROPOLITAN REGION. THE AREA IS NOTED FOR THE HIGH MOBILITY OF THE POPULATION WHICH, PRESUMABLY, EXTENDS TO POTENTIAL OFFENDERS. ADJACENT AREAS WERE DETERMINED BY WHETHER CITY BOUNDARIES WERE SHARED AND WHETHER INTERACTION BETWEEN THE COMMUNITIES WAS SIGNIFICANT. POLICE INPUTS WERE MEASURED AS ALL SWORN OFFICERS REGULARLY ASSIGNED TO STREET PATROL. CRIMES MEASURED WERE DIVIDED INTO THE GENERAL CATEGORIES OF PROPERTY OFFENSES AND VIOLENT OFFENSES. PROPERTY CRIME SPILLOVER WAS SHOWN TO BE SIGNIFICANT, WHILE VIOLENT CRIME WAS NOT; HOWEVER, ALTHOUGH THE LAW ENFORCEMENT DIFFERENTIAL INDICATES A SIGNIFICANT NEIGHBORHOOD EFFECT FROM THE PROVISION OF POLICE SERVICES, THE RELATIVE MAGNITUDE OF THE EFFECT IN EACH ADJACENT COMMUNITY APPEARS TO BE SMALL. AN INCREASE IN DETERRENCE RESULTING IN AN AVERSION OF ABOUT $2,000 OF SOCIAL COSTS WOULD EXPORT ABOUT $600 TO $700 IN SPILLOVERS, A RELATIVELY MINOR NET EFFECT. IT IS ADVISED THAT THE RESULTS PRESENTED ARE SUGGESTIVE RATHER THAN CONCLUSIVE AND THAT ADDITIONAL EMPIRICAL TESTS ARE NEEDED BEFORE FIRM POLICY IMPLICATIONS CAN EMERGE. TABULAR DATA ARE REPORTED. (RCB)