Now if half our patients bitten by a dog are going to get an infected wound, and by using antibiotics we can stop that happening just once in every eight times, then we save six patients in every 100 having an infected bite. So even in Middlesborough our prophylactic antibiotics won't stop every infection, but perhaps enough to make it worthwhile. This is a difficult area. Patients want to know their chance of getting better or being harmed, and that includes influences from all sources. But that is a simple example.
Most circumstances are more complex.
DL Sackett, WS Richardson, W Rosenberg, RB Haynes. Clinically useful measures of effect in binary analyses of randomized trials. G Chatelier et al. I've just been bitten by a dog. Applying overviews in meta-analysis at the bedside.