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Updated: Aug 8, 2026

ScanLag: High-throughput Quantification of Colony Growth and Lag Time
Published on: July 15, 2014
How do we interpret the recent dramatic increase in the time to earn a Ph.D.?
1Population Division, U.S. Bureau of the Census, Washington, D.C. 20233, USA.
Abstract:
A 1962 recipient of a Ph.D. was an average of 10.13 years from receipt of a B.A.; a 1992 recipient was an average of 12.55 years. Some authors have suggested that if the B.A.-year cohorts were compared instead of the Ph.D.-year cohorts, the average time to earn a Ph.D. would not show such a drastic increase. The author recognizes the problem with the Ph.D.-year data, but uses these data with a standardization-decomposition technique to show that 75 per cent of the increase in the time between the B.A. and the Ph.D. in 1992 was due to the change in the age-sex structure of Ph.D. recipients in favor of more women and older persons.
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