Despite the substantial resources devoted to the review process, it is unclear whether publicly funded research closely adheres to the original grant proposal. Using natural language processing techniques on 449 research grants awarded to about 900 scientists from a large European research university in 2000-2018, we document the deviations between pairs of grants and publications that acknowledge the grant. We analyze the antecedents of these deviations, focusing on the role of new team members, i.e., those co-authoring papers with the grant holders but who were not co-applicants of the grant. In addition, we examine whether there are differences in scientific impact between publications exhibiting larger deviations when compared to those closely aligned with the original proposal. Our findings reveal that publications with co-authors joining the team from outside the grant holders’ university (“external scientists”) tend to deviate more from the grant proposal. Conversely, first-time collaborations with junior external scientists align more closely with the original research plan. We theorize that these results are consistent with a trade-off between new team members fostering the knowledge recombination process within the team and the “liability of newness” that they face. Finally, we find a positive association between deviations and scientific impact, which informs the debate on the added value of a detailed ex ante review of grant proposals and the mechanisms to allocate science funding.