What does it take for and R&D tax incentive policy to be effective?

We take a critical look at how to assess the effectiveness of R&D tax incentives. The net welfare gain is shown to be sensitive to a certain number of parameters. In particular, the deadweight loss associated with level-based tax incentives depends on the ex-ante R&D level. We report on the success of a past policy changes and simulate the effect of various parameter changes in the existing Dutch R&D tax incentive scheme. We show that this policy is more effective for small firms than for large firms. We end with a discussion of the pros and cons of volume-based versus incremental R&D tax incentives.