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Comment by AnimalMuppet | Hacker News Reader

But even if they had used it as intended, how could you tell whether it works? How do you tell the difference between "there were going to be crimes there, but you patrolled there, and because you patrolled, there were no crimes" and "there were not going to be crimes there, whether you patrolled or not, so your patrol did exactly nothing."

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There are really two questions here, which should be tested separately:

(1) Is the software significantly predictive? Test the software's predictions against actual crime in areas with no patrols.

(2) Are patrols effective deterrents to crime? Observe the area in question with and without patrols. (I wouldn't be surprised to learn there are already such studies.)

If both (1) and (2) yield positive results, you can then use the software to direct patrols and see if the method itself is effective at reducing crime; which would also serve to further confirm (2).

Of course, even if only (1) yields positive results, there would probably be other benefits to using the software to direct patrols, like reducing response times (which could also be tested).

well, if you're a guest on https://www.probablecausation.com/, then you would randomly assign teams to patrol using this software or not,and compare the changes in rates. sounds like geolitica isn't very careful or interested in results.

If you’re selling tiger-repellent rocks, the last thing you need is a solid controlled experiment to get in the way of separating rubes from their cash.

how could you tell whether it works?

The study of those questions and the reliability of your answers to those questions is called statistics and it is an entire branch of mathematics, usually with its own department at most universities.

if crimes (print "there are crimes anyways, the police are ineffective!") else (print "there is no crime, the police are ineffective!")

Experimentation and tracking results over time.

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