That would be an argument against any attempt to clean up crime that wasn't done at a greater-city-wide scale. And maybe that really is true - the only genuinely effective measures you can take to reduce crime have to be applied to a sufficiently wide area. I'm not sure if we have enough data points to draw that conclusion though.
Could be. It may also be a factor of whether the high crime area is the first or the last occurence, since in the case of it being the first, you cause a diaspora. Whereas if it's the last, then you're squeezing.
