1. a measure of the ability of an organization, work unit, or individual employee to produce the maximum output with a minimum investment of time, effort, and other inputs. Given the same level of output, efficiency increases as the time, effort, and other inputs taken to produce that level decrease. Also called industrial efficiency; organizational efficiency. See also organizational effectiveness.

2. in statistics, the degree to which an estimator uses all the information in a sample to estimate a particular parameter. It is a measure of the optimality of an estimator when comparing various statistical procedures or experimental designs. —efficient adj.