Communications - February 2010

cise. One of the few controlled studies
to date was carried out in the clothing
retail shops in 19991:
The ˲ purpose of installing the systems
was clearly defined: reduce the stock
losses through customer and staff theft.

The ˲ measures for stock losses were clearly defined: the number and value of stock losses was monitored, and any reduction of losses calculated as a percentage of sales profits during the same period.

Stock losses were measured four ˲ times—twice during a six-month period before and after the introduction of CCTV.

The ˲ efficiency was calculated in terms of how many years the system would have to operate at the observed level of effectiveness to recover its investment.

During the one-year period, they ˲ monitored for a number of side effects such as footfall, overall sales, customer assessment of shops, and so forth.

This illustrates that carrying out a meaningful assessment under controlled conditions requires significant resources and domain expertise, even for a conceptually simple study: the assessment was focused on a single crime, the monitoring environment was constant, and systems for measuring the impact were already in place. The results showed that stock losses were reduced significantly in the first three months of CCTV introduction— but then rose again. After six months, the average loss reduction was a near-insignificant £ 4—at an average capital expenditure of £ 12,000 per CCTV system, it would take 58 years to recoup the capital cost. In the end, only shops selling high-value fashion using high-end CCTV systems reduced stock

Paso Times6 reported in January 2009 that the program was not effective because only a dozen incidents had been reported. A spokesperson for the Governor of Texas responded that the problem was not with the technology, but the way its effectiveness was assessed. It may look like a weak argument, but it points to the key problem: How do you assess effectiveness of a security technology such as CCTV? How can you determine whether the results represent value for the money spent on technology, or privacy invasions that occur because of its existence?

The answer is conceptually simple: effectiveness of a particular deployment means that it achieves its stated purpose; efficiency means the desired results are worth more than the resources required to achieve them. But the execution of a study to measure them is a challenging and costly exer-

the sports advertising industry” to search
footage for suspects and incidents.
Since that technology is not quite ready,
London police publish images of sus-
pects on the Internet and ask the pub-
lic for help. Recruitment of untrained
members of the public to assist in CC TV
monitoring is a growing trend:
In a London housing project, resi- ˲
dents have been given access to CCTV
cameras, books of photos of individu-
als who had been warned not to tres-
pass on the estate, and a phone num-
ber to call if they spotted any of them.

In the tourist town of Stratford-on- ˲
Avon, residents and business can con-
nect their own CCTV cameras to an In-
ternet portal, and and volunteers who
spot and report crimes can win prizes
of up to £ 1,000.a
Approximately $2 million has been ˲
spent on Webcams for virtual border
surveillance at the Texas-Mexico bor-
der, enabling virtual local residents to
spot and report illegal immigration.

The involvement of untrained members of the public in surveillance harbors many potential risks to privacy, public order, and public safety (e.g, vigilantism) that must be identified and considered. But even leaving those concerns aside, early indications from the last project suggest this not a quick fix to make CCTV more effective. The El