The effectiveness of reliability programs and tools based on design maturity and complexity

Many modern companies view reliability as a critical consideration during design, but often fail in achieving the required level of reliability in their products. The reasons for failing to achieve a product line's required reliability are numerous, but it is clear that the lack of proper implementation of an effective reliability program is one of the main drivers for this lack of success. In working with a number of companies that produce products ranging from simple to complex and with a variety of maturities, it is clear that reliebility programs are not “one-size-fits-all”, and rather need to be tailored to a product's complexity and current life cycle maturity. This paper examines products at three different levels of complexity (Low, Medium, and High), and three different levels of maturity (Qualified, Deployed, and Field Proven). Data from product lines at a variety of combinations of these categories have been examined. Results of this analysis indicate that levels of reliability are highly correlated to complexity, with an increase in complexity resulting in a decrease in reliability. Additionally, product line reliability is also observed to increase with product line maturity. Neither of these results were unexpected, but the analysis also indicated that some reliability tools, specifically FMECAs and FRACAS implementation, were most effective in increasing reliability in all product complexity levels, whereas other tools, such as RBDA, were effective in some cases, but had a more limited effectiveness on less complex products.