Do security signs deter burglars?

Search this question and the highest-ranking pages lean on a familiar set of numbers: a University of Texas at San Antonio study said to show yard signs deter burglars; a claim that "46% of burglars avoid homes with alarm signs"; the evergreen "homes without security are 300% more likely to be burglarized." Try to follow any of them to a paper, a dataset, or a named author with a locatable publication, and the trail dies in a loop of blogs citing blogs citing a press release nobody archived.

This is not pedantry. Untraceable statistics are how an eight-dollar sign gets marketed as a security strategy. If a number cannot be checked, it cannot be weighed — you cannot know the sample, the question wording, the funding, or whether the figure was about signs at all. A common corruption: the real UNC finding that about 60% of burglars would avoid a home with an alarm quietly becomes "60% avoid homes with alarm signs." The alarm and the sign are not the same thing, and the difference is the entire question.

The rule for everything below: every number traces to a study you can locate, and industry funding is disclosed where it exists.

The central source is Kuhns and colleagues' 2013 UNC Charlotte survey of 422 incarcerated burglars, funded by AIREF, an alarm-industry research foundation — a conflict worth knowing, though the work remains the largest structured offender survey available. Its headline findings concern alarms, not signs: roughly 83% of burglars said they would try to determine whether an alarm was present before a burglary, about 60% would seek another target if one was, and over half would abort a burglary in progress on discovering one.

Signs appear in the study as part of a broader category. The top target-selection factors were the proximity of other people, escape routes, and "signs of security" — a bundle that includes alarm signs, dogs inside, and outdoor cameras. So a sign does register. But read carefully and its role is specific: it is one input into the burglar's judgment about whether an alarm actually exists, weighed alongside stickers, visible keypads, wiring, and the look of the property. It is also the cheapest of those inputs to fake, and burglars price that in.

Nothing in the study supports a standalone percentage for yard signs alone. That is precisely why the honest summary is a range — weak to moderate, as a contributing cue — rather than the crisp fake numbers the top results prefer.

Independent-ish support for the thing signs advertise comes from Lee's 2009 Rutgers School of Criminal Justice study of Newark, also AIREF-sponsored: neighborhoods with higher residential alarm density experienced fewer burglaries, with no measurable displacement of crime to neighboring homes. Industry funding, again disclosed — but note what the study is about. The alarm itself. Nobody has produced comparable evidence for vinyl.

The KGW-TV survey of 86 Oregon inmates (2017, journalistic rather than peer-reviewed) explains why the sign can never be the main event: occupancy dominates everything. Most burglars entered through unlocked doors and windows, essentially all knocked or rang first to test whether anyone was home, and a car in the driveway, sound inside, or a big loud dog were the strongest reasons to walk away. A sign does not answer a knock.

Then there is the economics. Signs cost a few dollars, no purchase verification required, and every burglar knows sign-only houses exist in quantity. A sign backed by nothing is the fake-camera problem printed on aluminum: a bluff that works until the first probe, and not a minute after.

The practical questions people actually type into search boxes, each answered from the evidence above:

Rank the cues by how consistently the two offender surveys treat them: people present or plausibly present comes first, big loud dogs close behind, then a discovered alarm, then visible cameras, and signs last — a supporting witness for the alarm, never the star. The pattern underneath is simple: the harder a signal is to fake, the more a burglar respects it.

One more entry belongs in the ranking even though it makes no claim at all. The randomized NBER lighting experiment (Working Paper 25798) — intensive lighting across 77 New York City public-housing developments — cut nighttime outdoor index crimes by roughly 36%, an effect that follow-up work found persisted about three years. Lighting does not assert that something will happen later. It changes the scene now, which is a different and better category of deterrent.

Honesty about the limits: both offender surveys are self-reports from burglars who were caught, the UNC study is industry-funded, and the KGW piece is journalism with a sample of 86. This is the best evidence available, and it is thinner than the confidence of the average listicle.

Every sign shares one structural weakness: it asserts a capability it cannot demonstrate. The interesting inversion is a system whose visible behavior is the advertisement — where what a passerby sees is not a claim about a response but the response itself, idling.

That is how an Automatic Property Defense System like PerimeterEye handles the signaling problem. Each night, an hour after sunset, its motorized tracking searchlights run a configurable Perimeter Sweep — a visible patrol of light that never crosses the property boundary. Someone sizing up the street is not reading vinyl; they are watching a property demonstrate that it sees and reacts. And if a verified intruder steps onto the property, the demonstration stops being ambient: a searchlight locks on and physically follows them, a live targeted voice describes them out loud, and a 130 dB siren with priority alerts and live video sits behind it.

No security system can guarantee prevention of every incident — and after the sourcing audit above, you should distrust anyone who implies otherwise. But there is a real difference between a sign that says something will happen and a property where something visibly does.