D-Efficiency - Determinant efficiency is a scaled value of the determinant of the information matrix. It is used as a measure of D-optimality. A D-efficiency fraction of one is best. D-efficiency compares the design to a theoretical (not always possible) orthogonal balanced design.
d-efficiency = [Determinant of the Information Matrix](1/k)/ Number of runs
Some design types have very low values of D-efficiency because they are designed for a different objective. The Central Composite designs have such low levels of D-efficiency that some writers use a basis other than the equation above; they compare the CC as a group, independent of other design types.