  This longitudinal study explores persistence in research productivity over
time. We examine the trajectories of the academic careers of 2,326 current full
professors in 14 STEMM disciplines, studying their lifetime biographical
histories and publication histories. Every full professor is compared in terms
of productivity classes (top, middle, bottom) with their peers at earlier
career stages. We used prestige-normalized productivity in which more weight is
given to articles in high-impact than in low-impact journals, recognizing the
highly stratified nature of academic science. Our results show that membership
in top productivity classes is to a large extent determined by being in these
classes earlier. Half of the current top productive full professors belonged to
top productivity classes throughout their academic careers. Half of the top
productive assistant professors continued as top productive associate
professors, and half of the top productive associate professors continued as
top productive full professors (52.6% and 50.8%). Top-to-bottom and
bottom-to-top transitions in productivity classes occurred marginally. The
combination of biographical and demographic data with raw Scopus publication
data from the past 50 years (N=1 million) made it possible to assign all full
professors retrospective to different productivity, promotion age, and
promotion speed classes. In logistic regression models, two powerful predictors
of belonging to the top productivity class for full professors were being
highly productive as assistant professors and as associate professors
(increasing the odds by 180% and 360%). Neither gender nor age (biological or
academic) emerged as statistically significant.
