Research at various manufacturers has shown that as production doubles, the hours required to make something falls by a fairly consistent percentage, on the order of 10 to 30 percent. As volume builds, workers become more productive. Edward Russell-Walling, 50 Management ideas your really need to know (Quercus) at 80, discusses the experience curve theory, but doesn’t explicitly apply it to a service context.
Still, it makes sense that increased experience increases efficiency. Other posts have alluded to the plausibility of an experience curve for law department attorneys who handle a number of transactions of a similar kind (See my posts of Nov. 6, 2006: delegate to go up the efficiency curve; May 31, 2006: the sigmoid curve of management initiatives; Feb. 2, 2008: specialist billers at law firms and learning curves; Oct. 10, 2006: core competencies and skill curves; and July 15, 2006 and June 20, 2007 # 1: Horndal effect of increasing productivity.).
We may not know how to measure the output of a contracts lawyer, but it makes intuitive sense that if that lawyer does twice as many more of a kind of contract, the time required to do the average one in that second batch drops by 10-30 percent.