Scientific innovation often comes from researchers who pivot across disciplines. However, prior work found that established researchers face productivity penalties when pivoting. Here, we investigate the consequences of pivoting at the beginning of a research career -- doctoral admissions -- when the benefits of importing new ideas might outweigh the switching costs. Using applications to all PhD programs at a large research-intensive university between 2013-2023, we find that pivoters (those applying to programs outside their prior disciplinary training) have lower GPAs and standardized test scores than non-pivoters. Yet even conditional on these predictors of admission, pivoters are 1.3 percentage points less likely to be admitted. Examining applicants who applied to multiple programs in the same admissions cycle provides suggestive evidence that the admissions pivot penalty is causal. This penalty is significantly smaller for applicants who secure a recommendation from someone within the target discipline. Among those admitted and enrolled, pivoters are 12.9 percentage points less likely to graduate and do not show superior publication performance on average or at the tail. Our results reveal the substantial costs of disciplinary pivoting even at the outset of research careers, which constrain the flow of new ideas into research communities.

翻译：科学创新常源于跨学科转向的研究者。然而，先前研究发现，资深研究者转向时面临生产率损失。本文探究研究生涯初期——博士招生阶段——转向的后果，此时引入新思想的收益可能超越转换成本。基于2013-2023年间某大型研究型大学所有博士项目的申请数据，我们发现转向者（申请其先前学科训练领域之外项目的申请人）的GPA和标准化考试成绩均低于非转向者。即便在控制这些录取预测因子后，转向者的录取概率仍低1.3个百分点。通过考察同一录取周期内申请多个项目的申请人，我们获得暗示性证据表明录取环节的转向惩罚具有因果性。若申请人能获得目标学科领域内推荐人的支持，此惩罚显著减小。在已录取并注册的学生中，转向者的毕业概率低12.9个百分点，且其平均发表表现或尾部表现均未呈现优势。我们的研究揭示了即使处于研究生涯起点，学科转向仍会带来显著成本，这限制了新思想向学术共同体的流动。