Refers to a development model elicited from actual data. The data were collected from organizations that contracted with the U.S. Department of Defense, who funded the research, and they became the foundation from which CMU created the Software Engineering Institute (SEI). Maturity Levels: a 5-Level process maturity continuum - where the uppermost (5th) level is a notional ideal state where processes would be systematically managed by a combination of process optimization and continuous process improvement.