THE MODELS WERE DEVELOPED, FIELD-TESTED, AND DOCUMENTED DURING A TWO-YEAR PERIOD ENDING OCTOBER 1975. DURING THE FOLLOWING 18 MONTHS, RECORDS WERE KEPT OF THE EXTENT TO WHICH THE MODELS WERE ACQUIRED BY OPERATING AGENCIES AND ACTUALLY USED FOR MAKING DEPLOYMENT CHANGES. THE NUMBER OF ACQUISITIONS RANGED FROM ZERO FOR ONE MODEL TO THIRTY-NINE FOR ANOTHER. OVER HALF OF THOSE WHO ACQUIRE THESE MODELS ACTUALLY USE THEM, AND, EXCEPT FOR ONE MODEL, NEARLY ALL USERS MAKE OPERATIONAL CHANGES BASED ON THE OUTPUT. DIFFERENCES AMONG THE MODELS ILLUMINATE THE IMPLEMENTATION.(AUTHOR ABSTRACT MODIFIED)...EB