Why You Can't Blindly Trust Neighborhood Alerts

This post, like many of my best ideas, started with an alarming email from my mom (Hi Mom!). The email carried the subject line “Book Festival” and it had a link to the schedule for Tulane's always excellent book festival.

Wait, that's the wrong email.

The alarming email had the subject line “Fwd: Alert:  Spike in Vandalisms near (Her Neighborhood)”.

The body of the email began:

“Dear (Mom),

20 Vandalisms near your neighborhood over the last 7 days. That’s 5.6 times more than average.”

Then it gives a list of the blocks with the purported vandalisms:

That all sounds very alarming, but a closer look shows the whole thing is incredibly deceiving.

The first sign that something is amiss is the incident they say occurred on Robert E Lee, a street that was renamed to Allen Toussaint in January 2022. Clicking on that link in the email gives more information about a potentially alarming vandalism nearby.

Buried below that, however, is a description of the incident that shows the whole alert is bunk: “CRIMINAL MISCHIEF. NULL. Charge Code: NULL. Item #: L-36789-20”.

The item number at the end is a unique identifier given by NOPD to each incident to signify. Critically, the letter at the beginning and last two digits tell us the month and year of the incident. This incident was from December (L being the 12th month) 2020.

There's also the fact that criminal mischief is a pretty expansive offense type that doesn't really mean vandalism.

Of the 20 vandalisms reported in the past 7 days, 12 of them occurred in 2020 and 8 occurred in 2021.

Seeing a clear error made me want to sign up for alerts to see what I might get. So I did, and a few days ago I got my first alert.

Clicking on the link gives the event description as:

“RESIDENCE BURGLARY. DISPOSITION: DUPLICATE (DUP). Disclaimer: This is from the New Orleans Police calls for service log. Information is subject to change.

Date of Crime

March 15, 2025 at 12:46 AM”

The email is alarming, but the event disposition being a duplicate gives some idea that the incident in question may not have actually taken place. An incident receives a DUPLICATE disposition if the same incident has been reported through another means, so if my burglar alarm goes off and both me and my alarm company call 911 then there will be two incidents created in the 911 system. One is noted as a duplicate and the other represents the response to the actual incident as a way to rectify the duplication.

To learn more I went to NOPD’s Calls for Service page and looked for this incident. It pops up right away alongside two other incidents at nearly the exact same time at the same address.

There are two item numbers related to this incident that carry a “Duplicate” disposition with one being a residential burglary and the other being a burglar alarm. The third item number associated with this incident is a burglar alarm with a “Necessary Action Taken” disposition, suggesting to me that this is essentially the item number of record for this incident.

This disposition most likely means the officers showed up to a burglar alarm, made sure there was no danger, didn’t see evidence of a crime, and left without writing up a report of something more serious. To me this incident reads as a burglar alarm went off, it was reported to 911 multiple times — most likely by the alarm company, perhaps a concerned neighbor and/or the resident, and eventually was turned off and identified as a false alarm.

The vast, vast majority of burglar alarms reported to 911 are false alarms (in that there’s no crime occurring), so it would be most surprising if this was an actual burglary. Lacking any evidence of this, however, it feels safe to say that a burglary did not occur and the alert sent to my inbox was unnecessary.

Crime data can be messy and confusing. This fact is doubly so when using essentially raw crime data being published by agencies. And it's triply (quadropoly?) so when dealing with 911 Calls for Service. Just because somebody made a 911 call does not mean a crime occurred, and a system that blindly alerts nearby residents of Calls for Service without taking into account other factors that provide context is adding more confusion than clarity.