WITH A 1974 POPULATION OF 131,700, ADA COUNTY IS THE LARGEST POPULATED AREA IN THE STATE AND HAS CONSISTENTLY HAD THE STATE'S HIGHEST ROBBERY FREQUENCY. DATA ON ROBBERIES, EVENT CHARACTERISTIC, VICTIMS, AND APPREHENSIONS WERE OBTAINED FROM POLICE AND SHERIFF'S DEPARTMENTS, THE COUNTY PROSECUTOR'S OFFICE, THE DISTRICT COURT, THE IDAHO STATE CORRECTIONAL INSTITUTION, AND THE COUNTY JUVENILE DETENTION CENTER. FROM 1974 TO 1978, ROBBERIES IN THE COUNTY INCREASED BY 54 PERCENT, WHILE THE POPULATION INCREASED BY 10 PERCENT. ROBBERIES OF CITIZENS ON THE STREETS OR IN THEIR HOMES DECREASED. THE PERCENTAGE OF PEOPLE ROBBED OF PERSONAL PROPERTY BY PEOPLE THEY KNEW INCREASED FROM 29 PERCENT IN 1974 TO 59 PERCENT IN 1978. OVER HALF THE 1978 ROBBERIES OCCURRED IN THE LAST 3 MONTHS OF THE YEAR. CONVENIENCE MARKETS, THE MOST FREQUENT SINGLE SITE FOR ROBBERIES, DROPPED FROM 40 PERCENT OF THE SITES OF ROBBERIES IN 1974 TO 17 PERCENT IN 1978. GAS STATIONS WERE AMONG THE LEAST FREQUENTLY ROBBED SITES IN 1974, BUT WERE SECOND IN FREQUENCY IN 1978. THREE-QUARTERS OF 1974 LOSSES WERE UNDER $200, COMPARED TO 47 PERCENT OF 1978 LOSSES. THE 1978 STATISTICS SHOWED INCREASES IN ROBBERIES BY FEMALES, ROBBERIES COMMITTED BY LONE INDIVIDUALS, AND USE OF WEAPONS. FEWER VICTIMS WERE INJURED IN 1978 THAN IN 1974. THE 1978 DATA ALSO INDICATED THAT IF OFFENDERS COULD BE IDENTIFIED, THEY WERE LIKELY TO BE ARRESTED. THE PERCENTAGE OF ROBBERIES CLEARED BY ARREST REMAINED CONSTANT AT 32 PERCENT. THE NUMBERS OF ADULTS ARRESTED REMAINED CONSTANT, BUT THE NUMBER OF JUVENILES ARRESTED QUADRUPLED. THE PROPORTIONS OF ADULTS BONDED DECLINED, WHILE THE PROPORTION IN JAIL AWAITING LEGAL PROCESS ROSE. BETWEEN 1974 AND 1978, PROSECUTIONS ROSE BY 35 PERCENT, CONVICTIONS BY 25 PERCENT, AND INCARCERATIONS BY 54 PERCENT. ARRESTS NOT PROSECUTED FELL FROM 57 PERCENT IN 1974 TO 19 PERCENT IN 1978. TABLES, FIGURES, AND FOOTNOTES ARE INCLUDED. (CFW)