Median PhD time 7.3 years; postdoc avg 4.5 years; 15-23% tenure-track placement

NCSES Survey of Earned Doctorates: 2023 and supporting career-trajectory studies establish:

• Median total time from grad school start to PhD: 7.3 years.
• ~43% of PhD candidates have not completed within ten years (Council of Graduate Schools 2008).
• Median postdoc duration: 4.5–4.6 years (Kahn & Ginther 2017; Woolston 2020).
• ~15-23% of postdocs eventually secure tenure-track placement, depending on field.

The implication for research data preservation: the person who understands a dataset's content, format, and storage location is, on average, within a few years of leaving the institution that holds it. The architectural fix C-0017 calls for is preservation independent of any one researcher's continued participation; the demographic data here is the empirical input that makes "personnel turnover as preservation event" a steady-state property rather than an exceptional case.