I believe that gang stage is either the stages in which a gang develops.
1. Being gang leaders become aware of drug markets outside of major urban areas.
2. Develop a plan for go to a city without gangs.
3.gang members move to a new inner city neighborhood
4. More members arrive to recruit.
The stages explain wether competition between rival gangs or how the drugs increase.
Another reason is the series/stages of where a dawning realism process becomes important. Groups generally for artistic stuff or such.
Sorry if neither are correct, I found both through quizlet. Hope I helped :)