Modeling techniques: A repetitive cycle of modeling, testing, and redesign through final production specifications is crucial to eliminating a system's weak links

The design of a reliable system begins with the earliest feasibility studies and continues through final production blueprints. An initial electronic system design has only 10 to 30 percent of the reliability (mean time between failures — MTBF) of the final product. To increase this, design engineers undertake a repetitive design cycle, modeling reliability, testing predictions in the laboratory, and isolating areas that need improvement and redesigning them. This process is called “reliability growth” and must be carefully planned in order to achieve acceptable reliability by the time the product is ready for production.