"it should have produced quantifiable reduction in crime."  

If the dangerous offenders are kept in jail and the other  offenders were released, minor and non-dangerous offenses might very well have increased instead.   

Looking at the arrest records as they make the R-G, there seem to be quite a few who have been arrested over and over under the catch-and-release plans currently in effect.

How many burglaries and car clouts and sentences of probation do most of them have?