Increasing use of Benefit-Cost Analysis (BCA) in ex ante research evaluation has not been accompanied by consensus on the increased returns flowing from the evaluation effort. There are likely to be a wide range of views held by researchers, agricultural economists and research managers on how evaluation can be made more effective. The paper draws on the author’s experience in the evolution of BCA in research evaluation to propose how the current state of the art might be advanced. A BCA calculator is presented which enables a BC ratio to be simply and accurately determined. Inputs are total costs and their duration, potential benefits, and the adoption lag and rate. The adoption data, for example, is used in a table to look up the appropriate factor for the sum of discounted benefits. The calculator is likely to be seen as a somewhat oblique approach for those now accustomed to using the same inputs in a spreadsheet. However, the more likely role is as an introductory tool for researchers and research managers which is easier to understand, convenient and transparent. Further, the calculator shows that the effort in BCA calculations is trivial compared to that required to determine the input data. The calculator could also add to an evaluation approach which is competitive and indeed superior to more intuitive and less accountable approaches to resource allocation decisions. More widespread use of ex ante BCA, coupled with ongoing monitoring, are seen as the essential priorities for research evaluation. Monitoring can convert estimates of key inputs such as adoption patterns from an artful art to a science.