If something a law department does accomplishes the objective, what was done was effective. For example, if a department cross-trains paralegals, who are thereafter able to do the second job, the effort was effective. Or if the department negotiates a discounted billing rate with a firm, that was effective.
A separate notion is the effective action’s cost, which captures the key idea of efficient. Efficiency measures the resources required to accomplish something. If a competitive bid process costs $100,000 and saves only $100,000, then while effective it is far from efficient. If the $200,000 matter management system cannot plausibly show equivalent or greater savings, it is not an efficient management initiative (See my posts of July 31, 2005, Nov. 19, 2005, May 1, 2005, and June 16, 2006 on the ROI of various management actions.).