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Comment by ncr100 | Hacker News Reader

Only 1,500 police in SFPD? How does this even work?

What's the minimum number of officers per capita in a major city?

1,537 police in San Fransisco is a bit below average per capita, but not dramatically so. It's goal of 2,100 officers puts it about equal to the nationwide average.

There may be a non-linear relationship. It's 1/2 the ratio as NYC.

Please remember that the legal city of SF is quite small, compared to the area you think of as SF.

The city and the county are both the same 7x7 mile area comprising the top of the peninsula.

The 2 large park areas act as de facto boundaries. The hills and major roads also split things up. Only the NE 2/3 of the city and county is really urban, taking the area of proper SF from 50 sq mi down to about 20 if that.

I'm not sure if that national average is a good benchmark or not (maybe there is some sort of argument for how urbanized society has become) but my guess would be that there is some density factor. SF is something like 850k people pre-pandemic on 49 square miles. While it's not one of the biggest in absolute amount of people, it is the second(?) densest. I would suspect that a city of same population but 1/4 density would not need the same amount of cops.

update: I am guessing this is what your non-linear part is about; I missed that on first read.

It is the 21st densest city in the US, but most of them are small. NYC and Paterson, NJ (150k) are both denser.

I have no idea which way density argues. It means that cops are denser at the same per capita numbers which means their proximity to the highest priority should be closer. So faster emergency response. I don't know why a denser area would need more police, but I could be very wrong on that.

My argument (guess really) for why density necessitates more cops is that the opportunity for criminals also increases with density.

My thinking goes something like: a line of densely parked cars up Polk street with a bunch of people with their phones out at night making it hard to tell who is holding a flashlight probably means you need more cops patrolling the area to prevent crime vs my now suburban street with a few cars and no one walking at night means it would both be easy to spot opportunistic burglars and unlikely they'd hit up my street mostly for lack of targets.

I, too, could be wrong as I am saying this with no data.

You definitely need more cops to patrol the first example, but it also has far more people. It might take 20 times or more as long a street in the suburbs to get the same total people.

> I don't know why a denser area would need more police

Plenty of commuters, shoppers/diners, and criminals from outside SF, so number of police officers per city resident is not a very good metric.

East of Chinatown is an interesting area. About 10 years about, the cops there had a pleasant way about them. They're still pigs and monopolize violence unequally, largely for whoever lives highest on Nob Hill or The Presidio. I bet they're glad they're not certain LA cops who are effectively unpaid UberEats for some residents.

A new paper, The Injustice of Under-Policing, makes a point that I have been emphasizing for many years, namely, relative to other developed countries the United States is under-policed and over-imprisoned.

https://marginalrevolution.com/marginalrevolution/2022/08/st...

lock people up much longer and you don't need people keeping them in line on the streets. with the added benefit of not having to worry about national headlines in case barney fife decides to get extra beat-y

There is a table of fairly recent per capita numbers for the 50 largest US cities in the article: https://www.wweek.com/news/2022/09/28/portland-ranks-48th-am...

https://www.governing.com/archive/police-officers-per-capita...

Looks like between 15-20 cops per 10k. 800k would be right around 1500.

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