The process used to design quality into products, service, or processes during the product development phase. It is always better to "start with quality" rather than to try and "build quality in."
Quality by Design (QbD) is a concept first outlined by well-known quality expert Joseph M. Juran in various publications, most notably Juran on Quality by Design. Juran believed that quality could be planned, and that most quality crises and problems relate to the way in which quality was planned in the first place.
While Quality by Design principles have been used to advance product and process quality in every industry, and particularly the automotive industry, they have most recently been adopted by the U.S. Food and Drug Administration (FDA) as a vehicle for the transformation of how drugs are discovered, developed, and commercially manufactured.