Measuring the overall success of product development efforts has been frustrating because there is no generally recognized metric to measure effectiveness. The R&D Effectiveness Index is introduced to address this need. It measures effectiveness by comparing the profit from new products to the investment in new product development. The article provides the details for calculating the index along with alternative interpretations. Michael McGrath and Michael Romeri report that this index was validated through a study of 45 electronic systems companies. They found a strong relationship between the R&D Effectiveness Index and other performance factors and believe that the R&D Effectiveness Index can be used to compare perform- ance, measure improvement, and evaluate business units. Its application is illustrated in a case study.