We use a rigorous three-stage many-analysts design to assess how different researcher decisions—specifically data cleaning, research design, and the interpretation of a policy question—affect the variation in estimated treatment effects. A total of 146 research teams each completed the same...

Time-limited in-work credits are cheaper, and more targeted, than conventional in-work credits, but are thought to have small to zero long-term impacts. We study two time-limited in-work credits introduced in the mid-2000s in the UK and find they reduced welfare participation and increased...