Teleoanalysis can provide the answer to questions that would be obtained from studies that have not been done and often, for ethical and financial reasons, could never be done

Once a causal link has been established between a risk factor and a disease it is often difficult, and sometimes impossible, to determine directly the dose-response relation. For example, although we know that saturated fat intake increases the risk of ischaemic heart disease, the exact size of the effect cannot be established experimentally because long term trials of major dietary changes are impractical. One way to overcome the problem is to produce a summary estimate of the size of the relation by combining data from different types of study using an underused method that we call teleoanalysis. This summary estimate can be used to determine the extent to which the disease can be prevented and thus the most effective means of prevention. We describe the basis of teleoanalysis, suggest a simple one-step approach, and validate the results with a worked example.