text: open crime data can help, by finding and proving the gaps between perception of criminality and 
  
  reality. Belleri, for example, notes that residents of Milan consider the outskirts of their city more 
  
  dangerous than downtown Milan, while Londoners think the opposite about London... but in both 
  
  cities the truth emerging from data is exactly the opposite (at least for certain categories of crime) of 
  
  what their residents believe. 