We have plenty of reasons to not delegate after all, hiring others to work under you is costly, and coordinating them takes up your time and theirs.
These costs are highly visible, while the benefits are sometimes less so. The upshot often is managers doing too much themselves. What does this cost?
We turned to the law profession, where partners delegate legal work to associates (and nonlegal work to others, though we did not investigate this). We used data from thousands of law offices on how much partners make, how many associates work with them, and how much those associates and other staff cost the firm in salary and benefits. We combined this data with an economic model to estimate how much lawyers benefit when they work with associates.