Perspectives: answering questions about quality improvement: suggestions for investigators.

'Does it work?' is not the only question that practical improvers have of those investigating of quality improvements. They also want to know, 'Will it work here? What conditions do we need to implement and sustain it? Can we adapt it? How much will it cost and save? Is there enough evidence to spread it?'This perspectives article describes methods that investigators can use to answer these questions about improvement changes and improvement methods. It suggests that one reason why research is underused by improvers is because there is little research that answers these questions that would enable improvers to decide whether or how to implement an improvement in their local setting. It shows improvers that answers are possible and where improvers might find research and reports which answer these questions. It is based on reviews of research and reports about methods for producing valid and actionable knowledge to answer these questions. It describes a new 'quality improvement investigation movement' which is uniting applied researchers and improvers to use innovative methods to answer these questions. These investigators recognize the strengths of the randomized controlled trail method, and how easy it is to draw the wrong conclusions from data generated using lower cost and more timely methods. It emphasizes how investigators can choose a method suited to each question, describe the limitations of the method and communicate to improvers the degree of certainty of their answers to the questions.