Postdocs’ lab engagement predicts trajectories of PhD students’ skill development

David F. Feldon, Kaylee Litson, Soojeong Jeong, Jennifer M. Blaney, Jina Kang, Candace Miller, Kimberly Griffin, Josipa Roksa

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


The doctoral advisor—typically the principal investigator (PI)—is often characterized as a singular or primary mentor who guides students using a cognitive apprenticeship model. Alternatively, the “cascading mentorship” model describes the members of laboratories or research groups receiving mentorship from more senior laboratory members and providing it to more junior members (i.e., PIs mentor postdocs, postdocs mentor senior graduate students, senior students mentor junior students, etc.). Here we show that PIs’ laboratory and mentoring activities do not significantly predict students’ skill development trajectories, but the engagement of postdocs and senior graduate students in laboratory interactions do. We found that the cascading mentorship model accounts best for doctoral student skill development in a longitudinal study of 336 PhD students in the United States. Specifically, when postdocs and senior doctoral students actively participate in laboratory discussions, junior PhD students are over 4 times as likely to have positive skill development trajectories. Thus, postdocs disproportionately enhance the doctoral training enterprise, despite typically having no formal mentorship role. These findings also illustrate both the importance and the feasibility of identifying evidence-based practices in graduate education.

Original languageEnglish (US)
Pages (from-to)20910-20916
Number of pages7
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number42
StatePublished - Oct 15 2019
Externally publishedYes


  • Doctoral education
  • Graduate training
  • Mentorship
  • Postdocs
  • Research skills

ASJC Scopus subject areas

  • General


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