Addressing radiology workforce issues

able (with the caveat that satisfaction is a particularly tricky area to measure well), evidence about impact, quality, safety and competence are complex, and may require more complex methods of assessment to be persuasive. Shorter waiting lists are indeed one effect of an intervention, but without knowing eventual outcomes for patients, that effect may be of dubious relevance. If the dominant approach to evaluation in task substitution/enhancement research remains predominantly to do with output (such as waiting list reduction), we will really have little idea of which approach to the development of new roles is most likely to be beneficial. We agree with Oldmeadow et al that more research into new roles is required. Definitive answers to important questions are needed, and it is important that the complexity involved in this type of research is not overlooked. In particular, patient health outcomes must be a core variable in that mix of complexity if we are to make persuasive statements about impact, quality, safety and competence.