Quality and Reliability
Quality is defined as the degree to which a product or service meets customer requirements, while reliability is defined as the probability that a system will perform its required function without failure over time.
The reliability of a product is directly related to the quality of the product. A high-quality product is typically more reliable. A low-quality product will invariably be of low reliability.
Quality, Reliability and Safety
Any product's three most important aspects are safety, quality and reliability. The term "safety" refers to the absence of injury or damage caused by an object or substance. The term "reliability" refers to the ability of a device or system to perform its intended functions in a predictable manner over time (or quality over time). Finally, the term "quality" refers to the degree to which a device or system meets customer requirements.
Safety and reliability are closely related concepts. If a product is designed to operate safely, it is likely to be highly reliable.
In general, the higher the level of quality, the greater the probability that the product will be safe and reliable.