Half of all the work that goes to external counsel goes because those lawyers know more about an area of law than does the law department. This finding comes from PLCLaw Dept. Quart., Vol. 3, Jan.-March 2007, at 15, based on a survey of mostly European law departments
This blog has explained that specialist legal knowledge, manpower, lack of confidence in internal opinions, and conflicts of interest drive outside counsel usage (See my posts of Aug. 16, 2006: brains versus brawn and CYA; and Dec. 28, 2006: second opinions.). What is new from this survey is a directional metric on what percentage of the services retained turns on specialist expertise.
To these four reasons I can add volatility and geography, which means that litigation often goes to outside counsel because it has high peaks of demand for time – just before hearings, or in the midst of a series of depositions – and may require travel.