The bathtub does not hold water any more

Abstract

Abstract This is the first part of a three part article under the general heading of ‘Off the bathtub onto the roller‐coaster curve’, a short version 1 of which was presented at the 1988 Annual Reliability and Maintainability Symposium in U.S.A. The other two parts, to be published in later issues of this journal, are entitled ‘The roller‐coaster curve is in’ and ‘Physical basis for the roller‐coaster hazard rate curve’. This three‐part article provides detailed discussions of the findings leading to the conclusions on the roller‐coaster characteristics for the hazard rate curve for electronics. Part 1 being presented here covers the discussions on problems with the bathtub curve. The problems include making erroneous decisions resulting in reliability demonstration risks against the manufacturers, windfall profits for satellite manufacturers, false claims in reliability growth and reliability prediction accuracy and stress screening shortfalls. More important than the erroneous short‐term decisions is the long‐term reliability engineering methodology development. It is critical that we must reshape the course of reliability methodology development away from the bathtub misconception.