There is no solid evidence that the huge amounts of money spent on airport security screening measures since September 11th are effective, argue researchers in this week's Christmas issue of the BMJ.
Most screening programmes around the world are closely evaluated and heavily regulated before implementation. They rely on sound scientific and cost-benefit evidence before they are put into practice. Is airport security screening an exception, ask Eleni Linos and colleagues?
They reviewed evidence for the effectiveness of airport security screening measures, comparing it to the evidence required by the UK National Screening Committee criteria to justify medical screening programmes.
Despite worldwide airport protection costing an estimated $5.6 billion every year, they found no comprehensive studies evaluating the effectiveness of passenger or hand luggage x-ray screening, metal detectors or explosive detection devices. There was also no clear evidence of testing accuracy.
The US Transportation Security Administration (TSA) defends its measures by reporting that more than 13 million prohibited items were intercepted in one year. But, argue the authors, there is no way of knowing what proportion of these items would have led to serious harm.
This raises several questions, they say, such as what is the sensitivity of the screening question: 'Did you pack all your bags yourself?' and has anyone ever said 'no'? What are the ethical implications of pre-selecting high risk groups? Are new technologies that 'see' through clothes acceptable and what hazards should we screen for?
While there may be other benefits to rigorous airport screening, the absence of publicly available evidence to satisfy even the most basic criteria of a good screening programme concerns us, they write.
They call for airport security screening to be open to public and academic debate.
Rigorously evaluating the current system is only the first step for building a future airport security programme that is more user-friendly, cost-effective and, ultimately, protects passengers from realistic threats, they conclude.