The gang flag is imprecise, for several reasons. First, only incidents that come to the attention of the police result in an Incident Report. If a crime is never reported, it won't be reflected in the data. Gang crime is undoubtedly under-reported, and I suspect more so than crime generally. Second, even if the crime is reported to the police, we may not realize that there was a gang tie. The relationship may not be apparent, or we may have victims, witnesses, and perpetrators who are no forthcoming and cooperative. Finally, the choice of the gang flag is based on the officers' opinion, and can be somewhat subjective. The threshold for identifying an incident as gang-related can vary from one officer to another.
Despite these limitations, the flags provide a quantitative indicator of what's going on, without which we would have no basis other than anecdotes for assessing gang-related crime. We initiated this flag in our Incident Reports in 2007, so we now have data for 6 years and 11 months. Here it is (click the table to enlarge):
I suspect this will surprise some people. It surprised me a little bit. Three recent gang-related murders certainly have raised some eyebrows around Lincoln, but the data would show a declining trend in gang-related crime overall. Except for vandalism the numbers are small, and do not lend themselves to any meaningful trend analysis. The most significant thing I can tell you from these data is that reported gang-related vandalism (almost exclusively consisting of graffiti) is falling significantly and consistently. Since vandalism accounts for over two-thirds of the total, that decline is driving the overall trend.
Despite the data, you cannot ignore the fact that three gang-related murders have occurred in Lincoln this year. The anecdotal evidence suggests an uptick in gang-on-gang violence, as well. The numbers may be small, but the warnings signs are clear in the intelligence information we collect. When I diced some of these data a bit more finely, I found that we had 14 gang-related incidents in 2011 that involved firearms, 26 in 2012, and 10 so far in 2013. That spike in 2012 was quite obvious to police officers, and resulted in some targeted strategies this year that have probably interrupted some (but not all) of this violence. No lack of effort by the bad guys, though (including this past weekend) : poor marksmanship has saved our bacon.