Washington, Feb 1 (IANS) Intensive screening makes airport security unsafe by targeting low risk passengers rather than those who pose real threats, and this is particularly true after 9/11, a new study says.

Illinois University computer science and mathematics professor Sheldon H. Jacobson, along with Adrian J. Lee at the Central Illinois Technology, explored the possibility of matching passenger risk with security assets.

Jacobson’s previous work indicates that resources could be more effectively invested if the lowest-risk segments, frequent travellers, for instance, could pass through security with less scrutiny since they are “known” to the system, the journal Transportation Science reports.

In the new study, Jacobson and Lee developed three algorithms dealing with risk uncertainty in the passenger population, according to an Illinois statement.

They found that risk-based screening, such as the Transportation Security Administration’s new pre-check programme, increases the overall expected security.

“A natural tendency, when limited information is available about from where the next threat will come, is to overestimate the overall risk in the system,” Jacobson said.

“This actually makes the system less secure by over-allocating security resources to those in the system that are low on the risk scale relative to others in the system,” Jacobson added, according to an Illinois statement.

Consequently, a larger proportion of high-risk passengers are designated for too little screening while a larger proportion of low-risk passengers are subjected to too much screening.

“One hundred percent checked baggage screening and full-body scanning of all passengers is the antithesis of a risk-based system,” Jacobson said.