The survey updated data on the 122 municipalities and eight of the 11 counties included in the earlier survey; it included data on all U.S. cities that ranged in population from 150,000 to 200,000 and a random sample of 284 municipalities with populations of 25,000 to 150,000. Regardless of the method used to calculate national estimates, dramatic increases in gang crime were shown from 1991 to 1993. The conservative estimate of nationwide gang-crime activity, based on law enforcement reports, is 8,625 gangs, 378,807 gang members, and 437,066 gang-related crimes for 1993. A more reasonable estimate is 16,643 gangs, 555,181 gang members, and 580,331 gang-related crimes for 1993. The number of gangs estimated for 1993 is a 76.7-percent or 241- percent increase over 1991 figures, depending on the approach used. The number of gang members estimated for 1993 is a 51.9- percent or 122.7-percent increase over 1991 figures, depending on the approach used. The number of gang-crime incidents estimated for 1993 is an 843-percent or 1,152-percent increase over 1991 figures, depending on the approach used. 3 exhibits and 12 notes