Researchers at the UNC Charlotte are recommending the best way to measure the effectiveness of programs that reduce police dispatches to burglar alarms. Traditionally, public safety agencies and regulators have utilized statistics showing the percentage of police dispatches where officers did not identify a crime when responding to the call. Researchers say that method can be misleading.
"Alarm systems are a proven method of protecting life and property," said Kristie Blevins, a Key Author of the report and Assistant Professor in the Department of Criminal Justice and Criminology. "Our study identified best practices in evaluating alarm systems."
The report notes that simply attempting to quantify the number of police responses caused by alarms fails to take into account the growing number of alarm systems. "Percentages have limited usefulness in demonstrating changes over time," Blevins said. "Model city ordinances, better equipment, public education, fines and other steps can substantially reduce the burden on law enforcement without changing the percentage of dispatches counted as false."
Blevins recommends a different approach called the "alarm factor." Put simply, it divides the number of alarm dispatches by the number of alarm permits. This takes into account the ratio of false alarm dispatches to the number of monitored alarm systems.
For example, a community utilizing best practices might have a false alarm rate of .25 (one false alarm per registered permit every four years). A city with no alarm ordinance might have a factor of .75 (three invalid alarms per registered permit every four years). By tracking the "alarm factor," cities can better determine how they are managing alarm systems to protect citizens while preserving police response. The alarm factor also allows communities to more accurately compare alarm rates with other cities to help identify best practices and create benchmarks to measure improvement.
For example, the Montgomery County, Maryland police department dramatically reduced its alarm factor over a ten year period from .73 (almost one false alarm per registered user every year and a half) to .19 (approximately one invalid alarm per registered user every five years).
"One of the advantages of this method," Blevins said, "is that a jurisdiction can accurately track its false alarm factor over time to see if the number of false alarms per registered user has changed. Also, alarm factor rates can be used when jurisdictions are measuring the effectiveness of alarm ordinances or technologies aimed at reducing unnecessary alarms."
"Reporting these rates over time is particularly informative," Blevins continued, explaining that the data can more easily be placed in chart or graph forms to determine trends and, ultimately, if specific new procedures have worked effectively to change the direction of the trend.
"We are seeing significant drops in alarm factors nationwide," said Stan Martin, Executive Director of the Security Industry Alarm Coalition (SIAC), which works with police agencies throughout the U.S. and Canada on alarm issues. "There is a decade-long downward trend in alarm dispatches, and now it can be clearly demonstrated utilizing the alarm factor calculation." said Martin "It is not uncommon to see commercial alarm factors below 1.40 and residential alarms factors at or below .30 in cities with recommended ordinances that are enforced."