New product development is indeed very important for companies. However, developing new products is a risky and uncertain process. In order to reduce the risks and uncertainties, companies need to evaluate their new product initiatives carefully and make accurate decisions. Although the outcome of a new product evaluation decision can be influenced by the environmental uncertainties that are beyond a company s control, companies can successfully improve the accuracy of their new product evaluation decisions. This article presents an integrated framework for understanding how various factors affect decision making in new product evaluation and provides guidelines for reducing their negative impacts on new product decisions. The results indicate that the quality of new product evaluation decisions is affected by four major sets of factors, namely the nature of the task, the type of individuals who are involved in the decisions, the way the individuals opinions are elicited and the way the opinions are aggregated. 2003 Elsevier B.V. All rights reserved.