In contrast to pharmaceuticals, new surgical and other invasive procedures often enter clinical practice without assessment of their safety and efficacy. There is usually no guidance on their use. As a result, patients are offered treatments without access to adequate information on the nature and likelihood of benefits and harms; clinicians are left uncertain as to which innovations to adopt; and hospitals and healthcare systems have difficulty managing the risks that these procedures pose.1

Why does this happen? A fundamental reason is the poor evidence base for new interventional procedures, which has a number of causes. Unlike new pharmaceuticals, procedures do not usually have a commercial sponsor, which makes research harder to fund. When procedures entail a medical device, manufacturers have some incentive to fund evaluations, but differences in the regulatory regimes for drugs and devices, and in manufacturers' priorities for investment in research, mean that randomised trials are scarce. For example, novel designs of hip prostheses came to market with limited evaluation of their clinical performance.2 When research exists, widespread reliance on study designs without …