Although membership in a gang often is depicted as a lifelong commitment, the typical gang member joins at age 13 and only stays active for about two years, according to a study at Sam Houston State University. "Gang membership is not a fixed identity or a scarlet letter," said David Pyrooz in an article published in the Journal of Quantitative Criminology. "Media and popular culture have led to misconceptions about gangs and gang membership, chief among them the myth of permanence, as reflected in the quote from West Side Story -'When you're a Jet, you're a Jet all the way, from your first cigarette to your last dyin' day'."

The study was based on the 1997 National Longitudinal Survey of Youth, a national representative sample of nearly 9,000 youth between the ages of 12 and 16 who were tracked and interviewed annually until their early twenties. The study found that only 8 percent of those youth identified themselves as gang members. Less than 10 percent of the members stayed in gangs beyond two years, and 20 percent joined gangs as adults.

"First, the results of this study demonstrate that gang membership is strongly age-graded, much like criminal offending," said Pyrooz. "While gang membership is overwhelmingly an adolescence-oriented phenomenon, the findings indicate that youth cycle in and out of gangs at distinct points in the life-course."

There are six pathways into and out of gangs, which include three that occur during adolescence, two that are maintained over a long period, and one that starts late in the teenage years and continues into adult. The study also found that 40 percent of the gang members were active as adults. Adult gangs were found to be a combination of carryovers from youth gang involvement and those initiated into gangs as adults.

Another interesting phenomenon from the study is that the youth gang population identified in the study didn't match the demographic profile from police. At age 13, females constitute 30 percent of gang members and Blacks and Hispanics about 45 percent of gang members. But by age 20, female gang involvement reduced to about 15 percent and Black and Hispanic gang involvement increased to nearly 55 percent of gang members. Alluding to the demographic disparities, "gender better mirrors law enforcement records than race and ethnicity," said Pyrooz.

This study can be used to develop better prevention and intervention programs by targeting appropriate age groups for these initiatives. For example, gang prevention programs targeting students in the 6th or 7th grade would be a good use of resources because most youth who join gangs begin in their early teenage years, and as early as ages 10 and 11. In addition, because many members join gangs as adults, it is important to understand and develop programming for this demographic.