In Registered Reports (RRs), initial peer review and in-principle acceptance occurs before knowing the research outcomes. This combats publication bias and distinguishes planned and unplanned research. How RRs could improve the credibility of research findings is straightforward, but there is little empirical evidence. Also, there could be unintended costs such as reducing novelty. 353 researchers peer reviewed a pair of papers from 29 published RRs from psychology and neuroscience and 57 non-RR comparison papers. RRs outperformed comparison papers on all 19 criteria (mean difference=0.46; Scale range -4 to +4) with effects ranging from little improvement in novelty (0.13, 95% credible interval [-0.24, 0.49]) and creativity (0.22, [-0.14, 0.58]) to larger improvements in rigor of methodology (0.99, [0.62, 1.35]) and analysis (0.97, [0.60, 1.34]) and overall paper quality (0.66, [0.30, 1.02]). RRs could improve research quality while reducing publication bias and ultimately improve the credibility of the published literature.