Product reliability provides a value to the customer. Reliability can distinguish products. Reliability means the product, service, or system will perform as expected now and in the future. Statisticians provide the language to discuss product reliability.
Statisticians and reliability engineers (often with significant reliability training) guide and perform critical reliability prediction, experiment, assessment, and assurance activities. Beyond the fundamental set of statistical tools, reliability has a set of specialized statistical techniques. Following are some examples connected to the various stages of product life:
Statisticians work with a cross-functional team to define a product and determine just how long the product should last. The reliability goal comes from technical capabilities and market expectations. For example, "99% of our cell phones should last under normal use for five years with 95% confidence." Also, for complex systems, statisticians determine the reliability goal for each module or subsystem.
Given the reliability goal and other constraints, the development team attempts to meet the reliability goal at the lowest cost. Analysis includes reliability predictions, often using part count methods or reliability block diagramming. Also, statisticians design prototype testing to catch defects and verify specified levels of reliability.
Testing and audits determine if the product continues to meet reliability targets. Plus, statisticians evaluate product or process changes to determine if the product continues to meet reliability targets.
Warranty is only one way customers provide feedback on the product's reliability. Conducting surveys, customer visits, and financial analysis all help determine customers' perception of the product's reliability. Are the early failures just isolated and random problems, or a sign of a class defect? Are the recent improvements reducing warranty cost and improving customer perception of reliability?
Statisticians in the reliability field work across many disciplines and business functions. Effective reliability engineers are part of the product team and part of every decision. The statistician must be able to work closely with a design team on component comparisons and, the same day, work with a financial team to set expected production volumes. With both teams, the common topic of product reliability is key to making decisions.