Sustainability in quality improvement: measuring impact.

'Sustainable value' considers patient and population outcomes against environmental, social and economic costs or impacts, providing a framework for driving sustainable improvements in healthcare for current and future generations. Measuring the impact of a quality improvement initiative on sustainable value is a new endeavour. For this to be both meaningful and useful, we must balance academic rigour (using a reproducible methodology to capture the most relevant and important impacts) against pragmatism (working within the constraints of available time and data). Using case studies, we discuss how the different variables of sustainable value may be measured in practice.