The payback of 'Payback': challenges in assessing research impact

My personal questioning of the impact of my research career in health economics subsequently led to a series of studies concerning the assessment of impact. That stream of research has emphasised, among other things: the importance of the 'counterfactual', that impact was the product of the system as a whole and only partially influenced by researchers; and that the timescales necessary to observe impact were long and varied. The lags involved mean that funders seek short-term indicators of long-term impact but our evidence suggests that measures of academic impact are poor predictors of the broader impact that may eventually arise.