At least researchers tend to display relatively consistent output within a field: http://resources.emartin.net/blog/docs/AgeAchievement.pdf

Generally, the top 10% of the most prolific elite can be credited with around 50% of all contributions, whereas the bottom 50% of the least productive workers can claim only 15% of the total work, and the most productive contributor is usually about 100 times more prolific than the least (Dennis, 1954b, 1955; also see Lotka, 1926; Price, 1963, chap. 2). Now from a purely logical perspective, there are three distinct ways of achieving an impressive lifetime output that enables a creator to dominate an artistic or scientific enterprise. First, the individual may exhibit exceptional precocity, beginning contributions at an uncommonly early age. Second, the individual may attain a notable lifetime total by producing until quite late in life, and thereby display productive longevity. Third, the individual may boast phenomenal output rates throughout a career, without regard to the career's onset and termination. These three components are mathematically distinct and so may have almost any arbitrary correlation whatsoever with each other, whether positive, negative, or zero, without altering their respective contributions to total productivity. In precise terms, it is clear that O = R(L - P), where O is lifetime output, R is the mean rate of output throughout the career, L is the age at which the career ended (longevity), and P is the age at which the career began (precocity). The correlations among these three variables may adopt a wide range of arbitrary values without violating this identity. For example, the difference L - P, which defines the length of a career, may be more or less constant, mandating that lifetime output results largely from the average output rate R, given that those who begin earlier, end earlier, and those who begin later, end later. Or output rates may be more or less constant, forcing the final score to be a function solely of precocity and longevity, either singly or in conjunction. In short, R, L, and P, or output rate, longevity, and precocity, comprise largely orthogonal components of O, the gauge of total contributions.

When we turn to actual empirical data, we can observe two points. First, as might be expected, precocity, longevity, and output rate are each strongly associated with final lifetime output, that is, those who generate the most contributions at the end of a career also tend to have begun their careers at earlier ages, ended their careers at later ages, and produced at extraordinary rates throughout their careers (e.g., Albert, 1975; Blackburn et al., 1978; Bloom, 1963; Clemente, 1973; S. Cole, 1979; Richard A. Davis, 1987; Dennis, 1954a, 1954b; Helson & Crutchfield, 1970; Lehman, 1953a; Over, 1982a, 1982b; Raskin, 1936; Roe, 1965, 1972a, 1972b; Segal, Busse, & Mansfield, 1980; R. J. Simon, 1974; Simonton, 1977c; Zhao & Jiang, 1986). Second, these three components are conspicuously linked with each other: Those who are precocious also tend to display longevity, and both precocity and longevity are positively associated with high output rates per age unit (Blackburn et al., 1978; Dennis, 1954a, 1954b, 1956b; Horner et al., 1986; Lehman, 1953a, 1958; Lyons, 1968; Roe, 1952; Simonton, 1977c; Zuckerman, 1977).