Does Chemical Property Marking Deter Burglary? Results from a New Danish Experiment

RESEARCH QUESTION: Does enrollment of a burglarized household in a chemical property marking program reduce the risk of repeat burglary of the household? DATA: This randomized controlled trial utilizes a sample of 12,000 previously burgled households in North Zealand, Denmark, randomly divided into treatment, placebo, and control groups. METHODS: Treatment households received a letter describing local burglary problems and were offered a free chemical property marking kit including warning stickers to deter would-be burglars. Placebo households received a letter outlining generic methods of burglary prevention but were not offered a property marking kit. Control households were not contacted. RESULTS: A process evaluation shows that only 29% of the 4000-household treatment group both registered for the experiment and posted warning stickers as instructed. An intention-to-treat (ITT) analysis conducted after 15½ months indicated no statistically significant (p < .05) differences in follow-up prevalence rates of burglary experienced by treatment (4.6%), placebo (5.1%), and control (4.9%) households. CONCLUSION: The current experiment fails to find clear evidence that the posting of warning stickers indicating a once-burglarized household’s use of chemical property marking deters domestic burglary. Nonetheless, it remains possible to demonstrate an effect if a larger proportion of the experimental group could be persuaded to post warning stickers as instructed.