What do we do? The UK has very good geocoded crime data (down to the street level). A while back we noticed that the data also has information whether the crime was solved - so you can calculate clearance rates at small spatial levels.

Maybe not terribly surprisingly, our first instinct was to go and find some cool natural experiments, but... then we realised that we had little idea about basic facts - such as as what level clearance rates actually vary (neigbourhoods, cities, police forces?).