Management Science for Software Engineering [the broken link was removed]:
using the Theory of Constraints 5 focusing steps and the drum-buffer-rope solution for production flow problems, it was possible to increase the productivity of a sustained engineering department by more than 200%. In the final, quarter of the study period, a 25% increase (elevation) of the capacity constrained resource, produces a 25% increase in overall system throughput – just as the theory and model would predict.
Read the full paper by David Anderson, Microsoft, From Worst to Best in 9 Months – Implementing Drum-Buffer-Rope in Microsoft’s IT Department: [the broken link was removed]
Estimation was sucking up to 40% of capacity. Removing estimating produced a big and immediate productivity improvement [Table 3]. However, permission to stop estimating required a change in mindset from customers and internal management. They needed to stop the cost accounting for prioritization and budgeting.
An excellent article for those interested in project management and software development (as well as those interested in Theory of Constraints, of course). David Anderson continues to post excellent material detailing actual results.