Background: Systematic review and meta-analysis currently underpin much of evidence-based medicine. Such methodologies bring order to previous research, but future research planning remains relatively incoherent and inefficient since it does not formally consider how the new evidence will update existing knowledge. Objectives: To outline a formal and statistically rigorous framework for healthcare evaluation (Figure 1), aimed at increasing coherence and efficiency through making better use of information contained within the existing evidence base. This will lead to a reduction in the need for future studies, as well as ensure they are designed appropriately when they are needed. Methods: The two-part framework presented insists that an up-to-date meta-analysis of existing randomised controlled trials (RCTs) should always be considered before future trials are conducted. Such a meta-analysis should inform critical design issues such as sample size determination. The contexts in which the use of individual patient data meta-analysis and mixed treatment comparisons modelling may be beneficial before further RCTs are conducted are considered. Consideration should also be given to how any newly planned RCTs would contribute to the totality of evidence through its incorporation into an updated meta-analysis or other synthesis. Through illustrative example, we demonstrate how new RCTs can have very low power to change inferences of an existing meta-analysis, particularly when between study heterogeneity is taken into consideration. Particular consideration is given to the suitability of Cochrane reviews, including umbrella reviews, for forming the basis of such a framework. Suggestions are made regarding the addition of a new section to Cochrane reviews to make them more informative for people conducting new trials. Conclusions: While the collation of existing evidence as the basis for clinical practice is now routine, a more coherent, statistically rigorous and efficient approach to planning future RCTs to strengthen the evidence base needs to be developed. The framework presented is a proposal for how this situation can be improved and how Cochrane could play a central role in such a framework.