The Dutch Ministry of Economic Affairs and Climate just published our evaluation report on the R&D tax credit policy WBSO, for the period 2011-2017. The evaluation was done in a collaboration between Dialogic, APE and UNU-MERIT.
I worked on the econometric part of the evaluation, together with the people at APE. We found that the policy has a significant effect on R&D by private firms, but on average firms spend less extra R&D than the tax credit that they receive. We also find that the effect of the policy has gone down slightly in 2011-2016 as compared to the earlier period. You can find the press statement and a link to the full report here (in Dutch).