Last October I was invited to the first Brazilian National Meeting on Open Data. One of the things I brought back is lots of thoughts about the potential of Open Data about crime.

A laudable and not negligible part of this potential is in crime prevention. Another, equally important part is how much complete Open Data about crime can help:

• public administrators to plan and justify effective social policies
• and citizens to know what’s really going on, beyond prejudices and stereotypes.

Luis Fernando Linch is the current manager of the Crime Statistics Division of the State Secretariat for Public Security of Rio Grande do Sul. A couple of years ago, Linch worked with others on a report about traffic accidents in the Rio Grande Do Sul state. The report showed in detail where and when most accidents happen, as well as the profiles of involved drivers, thus helping to recognize and plan the best actions for drivers education and traffic law enforcement.

During the 2011 Open Data National Meeting in Brasilia, Linch presented even more impressive data.

As in many other countries, most killers of women in Brazil are people very close to them, who somehow also “announced” their intention through previous attacks.

During his talk, Linch explained that 91.23% of the cases of murdered women had been preceded by other attacks (often by the same people who would eventually kill them), with an average interval between killing and the last aggression of 205 days: “We know that women attacked would die”.

As chilling as they sound, statements like this can be of huge help for social planners and citizens alike. When Open Data of this kind are available, they don’t generate fear (not if they’re explained properly, anyway). On the contrary, it becomes much easier both to take decisions and to have them accepted. In Linch’s words, “the way to fight this is to democratize information”. Today, however, this doesn’t happen because of, among other things, disconnected actions, programs and bad databases not connected. That’s lack of Open Data, if you ask me.

With number like those, for example, it may be much harder to criticize statements like “we need to hire counsellors and psychologists specially trained to support women who are victims of physical attacks, even if this means that remodeling the city center will have to wait one more year”.

Heck, were it really necessary, with more Open Data of the right kind, one may even go the cynical route and prove that it makes financial sense because of all the money you’d save in investigations, trials and detentions…

The idea makes even more sense if you think that it’s general. Linch noted that similar statistics may be made about children and elder citizens. Finally, Linch showed maps of some cities in which you could see by yourself that the neighborhoods with the most homicides very much overlap with those inhabited almost exclusively by people who earn from 50 to 100% of the Brazilian minimum wage. Now, if you had similar numbers (from official sources, not “feelings” or politicians press releases) for your town, how would you explain them, and what would you do about it?