All that’s happening here is that the Mark 1.0 cop’s “intuition” and personal knowledge of crime patterns is being collectivized and quantified in a systematic way. It works for the same reason that experienced police officers have better arrest and clearance records than rookies — they know more about what’s actually happening in their areas and which persons are most likely responsible, and can adjust their actions accordingly for maximum effectiveness.

This isn’t rocket surgery. If you know that a same-MO burglar is hitting printing businesses three times a week between midnight and 2 am in area A, you stake out printers in area A between midnight and 2am. And if you know that Joe Bob Burglar who’s been known to use that MO was released from prison two weeks before the pattern began, you keep an eye on Joe Bob at the appropriate times. If (and this is where the software REALLY helps) that pattern is being repeated across different beats you can tie in the combined knowledge of the officers in those areas. The software helps police find the patterns and use their resources more effectively, especially across patrol area lines. They still have to make their cases based on crimes actually committed using real evidence, not pattern predictors. The courts don’t much care HOW you came to be (legally) watching someone’s public actions, they care about the suffiiciency and admissibility of the evidence.

Slippery slope? Yeah, when we suddenly acquire credible and court-admissible precognitive psychics by the boatload AND when our entire legal system is thrown out and replaced with one designed to corral and convict people who haven’t committed any crimes other than between their ears.