brightbehaviorist t1_iu964wd wrote on October 29, 2022 at 3:09 PM

Reply to comment by [deleted] in Ever felt unsafe walking along the streets of Baltimore late at night? by agentxstealth

It’s just not true that the absolute number of crimes “should” correlate with the ratio of trips interrupted by crime : trips attempted, even if both routes have been taken at least some minimum number of times (which your model doesn’t have any way of knowing, anyway). If you don’t understand this very basic bit of data science, it’s totally reckless for you to be offering people advice on where to walk.

Look, there were 485 murders in NYC in 2021, compared to 337 in Baltimore in the same period. But we all know better than to say that Baltimore is safer than NYC, because NYC has many times more people in it than we do. You have to correct for the base rate of population by comparing murders/100k residents or something. When you do that, you see that the count doesn’t correlate with the relative risk ratio at all!

If you don’t have the information you need for the denominator of the relative risk ratio, there’s no amount of “testing” that can show your model works.

agentxstealth OP t1_iu98mce wrote on October 29, 2022 at 3:27 PM

This is a good point, but as I stated previously, current crime hotspots do indeed have predictive value of where future crimes will occur. Moreover, I am not forcing the user to take a specific route, they have a plethora of options to choose based on their preferences for both speed and safety. If you don't believe me you don't have to download the app.

Also your whole comparison of Baltimore to NYC is completely dumbfounded because the user will be choosing between routes that go through the same city, with all route options having being taken a similar number of times. Hence if one route has a significantly greater number of crime hotspots that will almost certainly correlate with the crime:trips attempted ratio. Also as I said previously, the user can choose between multiple options and I am not forcing him to take any specific route.

Edit: brightbehaviorist I totally understand what you're saying that the crime:trips ratio would be a better indicator of the safety than just crimes, and I am working on integrating this into the algo. However, I think it is still very useful to see local crime hotspots along the route you're taking, and I has said before, the user can choose between a plethora of options based on their preferences (like google maps). Thanks for your feedback!