This paper draws attention to problems inherent in the routine application of the concept of additionality in evaluation. It exemplifies these problems by expressing them in a typology based on the perceived additionality of public R&D support and the strategic value of the R&D funded. Some categories are considered to represent successes of public R&D support and others to represent failures. The paper questions such routine assumptions, and uses empirical materials from EU framework programmes, a special case of public R&D programmes, to illustrate the problems. The paper ends by suggesting that the present system of evaluation rewards short-term success, and argues that it would be more beneficial to develop evaluation procedures that stretch over a longer period and are therefore able to pick up emerging areas of important technology supported by public programmes.