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What Actually Deters Burglars? (Evidence From Convicted Offenders)
By Kojiro Otani 6 min read
Short answer: Burglars are deterred most by anything that signals a break-in will be seen, heard, slow, or risky — nearby people or police, visible alarms and cameras, a barking dog, and boundaries that are hard to climb or enter. The evidence is consistent: most burglars are opportunists who pick the easiest target. In a University of North Carolina at Charlotte study of 422 convicted burglars, 60% said they would choose a different target if a home had an alarm, and 83% checked for security before attempting a break-in.
The most effective home security isn't about stopping a determined attacker — it's about making your property look like more trouble than the house next door. Decades of research, including interviews with convicted offenders, show burglary is overwhelmingly a crime of opportunity. Here's what the data actually says deters burglars, ranked.
What deters burglars the most?
The single biggest deterrent is the risk of being seen or caught — nearby people, police, or anyone who might notice. After that come visible alarms, outdoor cameras, dogs, and hard-to-enter boundaries. Below is how convicted burglars themselves rank the main deterrents.
| Deterrent | How strongly it deters | Why it works |
|---|---|---|
| People or police nearby | Strongest single factor (~64%) | Raises the chance of being seen and caught |
| Alarm system | ~53% deterred; 60% pick another target if present | Signals noise, alert, and a fast police response |
| Outdoor security cameras | ~50% deterred | Creates a record and signals an "alert" household |
| A dog (especially a large, loud one) | High for most offenders | Noise + unpredictability + attention |
| Hard-to-climb walls, fences & gates | Adds time, effort, and injury risk | Removes the easy access burglars look for |
| Visible security signage | ~25% deterred | Cheap signal that the property may be protected |
Figures: UNC Charlotte survey of 422 convicted burglars, summarised by Security.org and ScienceDaily. Percentages reflect the share of burglars who considered each measure an effective deterrent.
How do burglars choose a target?
Burglars choose targets to maximise reward while minimising effort and the risk of being caught. They look for homes that appear to hold valuables, are easy to reach and enter, and are hidden from view — and they avoid the opposite.
Offender-interview research (including ethnographic studies where burglars reconstruct their own break-ins) consistently finds:
- Most burglary is opportunistic. Over 75% of reconstructed burglaries were crimes of opportunity, and in the UNC study only 12% planned the burglary in advance while 41% described it as "spur of the moment."
- They weigh gain cues (signs of valuables inside) against risk cues (visibility, whether anyone's home, how easy it is to get in and out).
- They prefer properties that are unattended, easy to access, and screened from neighbours by walls, foliage, or poor lighting.
The practical lesson: you rarely need to defeat a master criminal. You need your home to lose the "easiest target on the street" competition.
Do alarms and security cameras actually deter burglars?
Yes — visible alarms and cameras are among the most effective deterrents, because most burglars actively check for them and will leave when they find them. In the UNC Charlotte study:
- 83% said they would try to determine whether an alarm was present before attempting a break-in.
- 60% said they would seek a different target if there was an alarm on site.
- If they discovered an alarm mid-attempt, about 50% would stop and another 31% would sometimes retreat.
One caveat keeps this honest: cameras deter far better than they catch. Some studies — such as a Lincoln, Nebraska review of cameras in a bar district — found cameras did little to help identify offenders after the fact. The value is in the visible signal beforehand, not the footage afterward. That's why a camera you can see beats a hidden one.
Does a dog deter burglars?
Yes — dogs, especially large, loud ones, rank as a strong deterrent in offender surveys. A barking dog adds three things burglars hate at once: noise, attention from neighbours, and unpredictability. In a separate survey of 86 incarcerated burglars, a "big, loud dog" was cited as a major reason to skip a house. A dog isn't a security system, but as a deterrent signal it punches above its weight.
What about lighting, fences, and physical barriers?
Physical deterrents work by attacking the two things burglars optimise for: easy access and low visibility. This is the core of CPTED (Crime Prevention Through Environmental Design), the framework police forces use worldwide.
- Lighting removes the cover of darkness. Motion-activated lighting also creates sudden, attention-drawing change.
- Boundaries that are hard to climb (high walls and fences finished with anti-climb spikes) remove the quick, quiet entry over a fence that opportunists rely on — adding time, effort, and visible injury risk before they ever reach a door or window.
- Clear sightlines (trimmed hedges, no hiding spots) raise the chance of being seen.
None of these has a tidy "deters X%" figure the way alarms do, but they target the exact decision factors — effort, access, and visibility — that every offender study identifies. Used together with a visible alarm or camera, they move your home firmly out of the "easy" column.
How long does a burglary take?
Most break-ins are fast: entry often takes under a minute, and burglars are typically inside for only 8–12 minutes. The FBI and security-industry figures commonly cite an 8–10 minute average, with some break-ins lasting as little as 90 seconds. Speed is the whole point — the longer an intruder is exposed, the higher the chance of being caught. Anything that slows entry or makes it noisy and visible works against that, which is why hardened, well-lit, alarmed properties get passed over.
What's the most cost-effective way to deter a burglar?
Layer cheap, visible deterrence with a hard perimeter — in that order. You don't need the most expensive system; you need the most off-putting front line:
- Make it look watched — a visible camera and/or alarm signage (the cheapest high-impact signals).
- Make it look occupied — timers on lights, no piled-up mail, a car in the drive.
- Make it hard to enter quietly — solid locks, motion lighting, and climb-resistant walls, fences, and gates.
Together these target every factor offenders weigh: reward, effort, and risk of being caught.
Frequently Asked Questions
What deters burglars the most?
The strongest deterrents are signs a break-in will be seen or caught — nearby people or police, then visible alarms, outdoor cameras, a loud dog, and hard-to-enter boundaries. In a study of 422 convicted burglars, 60% would choose another target if a home had an alarm.
Do burglars avoid homes with security cameras?
Mostly, yes. About 83% of burglars check for alarms and cameras before attempting a break-in, and around half consider visible cameras an effective deterrent. Cameras work best as a visible warning rather than as after-the-fact evidence.
Are most burglaries planned or opportunistic?
Overwhelmingly opportunistic. Over 75% of burglaries are crimes of opportunity; in the UNC Charlotte study only 12% were planned in advance and 41% were "spur of the moment."
Does a dog stop burglars?
A large, loud dog is a strong deterrent in offender surveys because it adds noise, attention, and unpredictability. It's not a substitute for locks and alarms, but it reliably pushes opportunists toward an easier target.
Do anti-climb spikes deter burglars?
There is no study measuring a single percentage for spikes, but they target exactly what burglars avoid — easy, quick, quiet access. By making a wall or fence slow and risky to climb, anti-climb spikes help move a property out of the "easy target" category that opportunistic burglars prefer.
How long does the average burglary take?
Entry is often under a minute, and burglars are usually inside for about 8–12 minutes. The faster they can get in and out, the lower their risk — so slow, noisy, visible properties get skipped.
Sources
- University of North Carolina at Charlotte — "Through the eyes of a burglar" (study of 422 offenders, J. Kuhns)
- Inside UNC Charlotte — study summary
- Security.org — Do security cameras deter crime?
- U.S. Office of Justice Programs — How Residential Burglars Choose Targets
- NIH/PMC — Burglar Target Selection: A Cross-National Comparison
Written by
Kojiro OtaniFounder of Saitani-Ya Co., Ltd. and creator of the Ninja Deterrent™ brand. Drawing on Japan's tradition of shinobi-gaeshi, he designs and manufactures anti-climb security spikes that pair real deterrence with architectural beauty — writing from first-hand experience in their engineering, production, and real-world installation.
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