Pork Barrel or Barrel of Gold? Examining the performance implications of earmarking in public R&D grants

•Earmarked projects receive lower peer review evaluation scores than non-earmarked projects, but do not consistently underperform in terms of research- and science-based outcomes.•Misalignment between peer review evaluation scores and research- and science-based outcomes can be explained by the presence of a peer review bias towards earmarked projects.•Challenges the dominant assumption that earmarked projects consistently underperform relative to non-earmarked projects.•Highlights the importance of considering a broad range of outcomes when comparing selection processes for allocating public funds through R&D grants.