Rationale for a Modified Duane Model

The Duane model for reliability growth involves a rate function which is an inverse power law and has an ``infinite´´ value at t = 0. The model is usually motivated entirely empirically. Here a probabilistic rationale is proposed via a reliability growth model involving the removal of design faults. This rationale results in a modified power law rate, finite at the origin. A wider class of rate functions should be investigated for NHPP models of reliability growth.