Deciding on suitability for treatment

This paper considers a particular argument from statistics, which concerns a treatment that is self-administered: it is argued that, since whenever the treatment is undertaken by people over 60, they fail to do it properly and incur grave infections; it should be withheld from this age group. Various objections to the argument, that the sample was too small, that poor training may be the explanation and that there are great variations in the capacities of the elderly, are considered. The conclusion is that it can be just and right to use evidence of this sort, but not in cases such as this, when it would be practicable and more reliable to 'screen' patients individually. A further conclusion is that, especially but not only in matters involving training and education, (1) the situation may change and (2) the facts may admit of more than one explanation.