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On the link you provided (https://www.neighborhoodscout.com/ca/san-francisco/crime) there's a "Source & Methodology" link which says "Raw data sources: 18,000 local law enforcement agencies in the U.S." and "Date(s) & Update Frequency: Reflects 2021 calendar year; released from FBI in Oct. 2022"

The FBI puts out one main source of crime stats - UCR. On the UCR site that I linked to: "The UCR Program includes data from more than 18,000 city, university and college, county, state, tribal, and federal law enforcement agencies." Those numbers aren't a coincidence.

UCR is the main data product that people use for (usually incorrect) analysis. The FBI itself says that the data is incomplete to the point that it should not be used as a way to determine the safety of a location.




They even discuss it in detail: "What makes NeighborhoodScout® Crime Data uniquely accurate? Most city neighborhood crime data are incomplete and inaccurate because crimes are reported by individual law enforcement agencies, rather than by city or town, and many cities – even small ones – have more than one agency responsible for law enforcement (municipal, university, county, transit, etc.). Even FBI data are reported by agency not by city or town, providing an incomplete assessment of city-wide crime counts. It is an agency-centric rather than locality-centric reporting method. If you use FBI data, you only get city-wide general counts, and only from one agency in the city, so it is generally incomplete for the city overall, as well as not specific to a neighborhood or address."

And further: Once we have these complete set of reported crime data, along with millions of geocoded reported crime incidents using a GIS, we begin our crime data development process.

The results are fine resolution, highly accurate crime data that are comparable nationally.

Our approach provides you the ability to look at small areas effectively.

In some cases a city agency is in charge of law enforcement, while in other areas it’s a county. In many cases it is more than one agency for a geographic area. Since the geography varies, it’s difficult to compare the scores among jurisdictions, or to get a true and complete picture of crime risk. This is why we use a relational database to assess the true count of reported crimes in a locality.

Although most agencies report, not all do. This creates holes in the data. Our method allows us to accurately fill in the holes based on the crime experience of many like locales, and provide accurate crime data for anywhere in the U.S.


The quote you posted offers no actual information about how they purport to plug gaps in the data:

> And further: Once we have these complete set of reported crime data, along with millions of geocoded reported crime incidents using a GIS, we begin our crime data development process.

> The results are fine resolution, highly accurate crime data that are comparable nationally.

> Our approach provides you the ability to look at small areas effectively."

Can you explain to me what their methodology is? Because this is just marketing-speak and doesn't provide any facts about how or why their analysis is accurate.

---

Edit: from their own site!

> Q. Why rank cities on safety even though the FBI cautions against it?

> A. This report and/or our data cannot and should not be used as a measure of the effectiveness of law enforcement due to the myriad factors that can contribute to crime in a community.

- https://www.neighborhoodscout.com/faq/top100dangerous#q9

This is literally taken from the FBI doc that I linked to earlier.




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