The 28:1 Grant/Sackman legend is misleading, or: How large is interpersonal variation really?
Lutz Prechelt · Repository KITopen (Karlsruhe Institute of Technology) · 1999
How long do different programmers take to solve the same task? In 1967, Grant and Sackman published their now famous number of 28:1 interpersonal performance differences, which is both incorrect and misleading. This report presents the analysis of a much larger dataset of software engineering work time data with respect to the same question. It corrects the false 28:1 value, proposes more appropriate metrics, presents the results for the larger dataset, and presents results of several further analyses: distribution shapes, effect sizes, and the performance of various significance tests.