"an analysis of more than 80 cases" out of 80 thousand. At this sampling rate, I'd suspect a large margin of error in any statistics.
Nevertheless, the study shows that tagging works as a method of triage; separating those who obey society's rules from the scoff-laws.
An interesting study would be to compare the sentencing authority's predictions of who will violate the tagging scheme. If they match the actual violators fairly well, then judicial discretion would be an even cheaper method of triage.
You've heard of "Disgusted, Tunbridge Wells"? Well, I live in Holland Park and I've Had It. Up to here! An old curmudgeon, I rant and rave about things I read, see or hear in the News. Frequently sarcastic, irreverent and libertarian; often wrong - but never uncertain.