This document reports on the final output of the OECD microBeRD+ project. Drawing on the outcomes of previous work, this study presents new evidence on the impact of business R&D support policies – tax incentives and direct forms of support – on business R&D investment (R&D input additionality) and the innovation and economic performance of firms (R&D output additionality). The report also provides an exploratory analysis of R&D spillovers.