More on statistics and the death penalty 

 There was a good  non-technical article  by Adam Liptak in the  New York Times  this weekend reviewing the renewed debate about the supposed deterrent effect of capital punishment (The web version of the article linked to seven different academic articles; many thanks to the editorial staff). I've blogged about this before ( here ) and tend to agree with those who say that there just isn't enough information in the data.  In that context, I particularly liked the quote from Justin Wolfers at the end of the article: 

 Professor Wolfers said the answer to the question of whether the death penalty deterred was “not unknowable in the abstract,” given enough data.

 “If I was allowed 1,000 executions and 1,000 exonerations, and I was allowed to do it in a random, focused way,” he said, “I could probably give you an answer.”  
  
Personally, I'd rather randomly allocate 1,000 electoral systems than 1,000 executions, but the point is well-taken.