As with Quality, discussions about Reliability can be just as arguable and difficult to grasp at the technical level - maybe even more so than Quality. But, again, we can drill-down to see how Reliability can be understood as a tool to enable product development and validation of product claims by us Techies.

Reliability issues such as product expectations, measurements, analysis and validation are outlined at the corporate level and then further distilled into concepts and entities that technical people can deal with, usually by Reliability Engineering or development engineers who are experienced with Reliability Engineering techniques.

Reliability Engineering (RE) is a discipline for designing tests and experiments, establishing evaluation techniques and analysis methods, measurement accuracy and precision and confidence levels. All this is intended to assure an acceptable probability that a functional entity* will continue to perform its stated function without stated failures under stated conditions for a stated period of time.

*Entity can be a system, a process, a product, knowledge or an activity. "The functionality of an entity is a discernable action, or any group of related actions contributing to a larger action, for which the entity is specifically employed, fitted, used or for which the entity exists."

From our 'Techie' viewpoint Reliability can be described as a discipline for establishing discrete and statistical guidelines, tests and evaluation methodologies to ensure that a product has an acceptable probability of meeting measurable or assessable goals that are firmly stated by the product stakeholders.

Take note of the term probability. This implies a statistical practice and it makes Reliability Engineering a bit different from Quality Engineering (see: http://www.weibull.com/). Two distinct levels of RE will summarize this difference.