Clearance rates don’t change all that much, but it’s interesting that when the homicide rate in New York was at it’s highest, the NYPD was also solving the highest precentage of murders. (1990 was the peak for murder in New York. The murder rate started going down after that.)

And now that the murder rate is so impressively down, so is the clearance rate. I have some theories about this, but it would make a good doctoral thesis for someone at John Jay, I think.

1970’s – The percentage of murders that went unsolved in New York is 37.6%.
1980’s – The percentage of murders that went unsolved in New York is 31.2%.
1990’s – The percentage of murders that went unsolved in New York is 35.2%.
2000’s – The percentage of murders that went unsolved in New York is 40.2%.*

*So far.