Contrary to popular belief, gang life is short-lived.

Researchers from Sam Houston State University found that though 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.

"Gang membership is not a fixed identity or a scarlet letter," researcher David Pyrooz said 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'."

For the study, researchers collected and analyzed data from a 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 20s.

They found that 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," Pyrooz said. "While gang membership is overwhelmingly an adolescence-oriented phenomenon, the findings indicate that youth cycle in an out of gangs at distinct points in the life course."

Researchers said their findings 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.