It's not what you say but how you say itBMJ 2007; 334 doi: http://dx.doi.org/10.1136/bmj.334.7608.1344 (Published 28 June 2007) Cite this as: BMJ 2007;334:1344
It is the job of the modern doctor to give patients the facts about a treatment, so they can make up their own minds about whether to accept it. But the facts—usually benefits and risks—can be framed in many different ways, and the method you choose could have a profound impact on the patient's enthusiasm for treatment. In one study, people were most likely to accept preventive treatments when they were given the number needed to treat (the average number of patients who must be treated to prevent one event). They were significantly less keen when the same treatments were described in terms of their potential to postpone, not prevent, disease.
The researchers sent a questionnaire containing one of three scenarios to a sample of healthy Norwegians. In each scenario the facts were the same—taken from published trials of a statin to prevent heart attacks or a bisphosphonate to prevent hip fracture—but the researchers' description of the facts was different. For both treatments, respondents “preferred” the number needed to treat option.
One explanation is that a number needed to treat sounds a bit like a gamble, say the authors. It implies that one lucky person will completely escape the feared outcome. People seem willing to bet that it will be them.