In December 2010 the city of Birmingham, UK installed the ShotSpotter, the controversial gunshot detection system. It cost approximately $257,000 to install and $36,000 each year to maintain but now, 20 months later, has now been deemed an outright failure. The BBC reports (emphasis added) ….

But just 20 months later ShotSpotter was judged to be a second failure.

In August 2012 West Midlands Police said of 1,618 alerts produced by the system since November 2011, only two were confirmed gunfire incidents.

What’s more, the force added, ShotSpotter had also missed four confirmed shootings.

In a system such as this, false positive are far worse than false negatives. False positives (report a gun shot that did not happen) waste limited and expensive police resources to investigate. False negatives (not reporting an actual gunshot) is simply the status quo before the system was installed. The real cost of this system was not the installation and maintenance, but the the wasted police resources investigating phantom gunshots.

He acknowledged there were “technical problems”, which caused the system to be less accurate than normal, but suggested this could have been avoided if the city had been more committed to the idea.

The classic “it would have worked if only we bought more of it”. We can only wonder how many more false positives would have been reported if they had expanded the system.

A review of the 22 injuries caused by guns in Birmingham’s west and central areas between April 2011 and March 2012 reveals that the majority were the result of air-rifles and BB air guns.

“A higher sensor density might permit such modified weapons to be detected, but the economic equation would, again, need to be reviewed,” said Mr Bedlock.

It’s not impossible that ShotSpotter will return to the UK. The Home Office notes that it is “down to each regional police force” as to whether it invests in the equipment.

But for now it seems this is one instance where the traditional trumps cutting edge tech – at least where British cities are involved.

Disclaimer: The author of this post has invented a knife-crime detecting system called StabSpotter. Utilizing patented acoustic technology StabSpotter can detect stabs from knives, swords, spears or bayonets that happen as far as 5 yards away from one of its sensors. It guarantees no false positives as long as every StabSpotter sensor is deployed at least 1 mile away from kitchens, hospitals, any sort of manufacturing, high schools which have not yet banned scissors and outdoor recreation areas.