See below image for the Process assessment systems diagram. The disciplined examination of the process es by an organisation against a set of criteria to determine capability of those process es to perform within quality, cost and schedule goals. Learn more in: The ISO/IEC 29110 Software Lifecycle Standard for Very Small Companies
Process Assessment Model — What is it? A Process Assessment Model (PAM) relates to one or more Process Reference Models. A PAM holds all details (so called indicators) to determine process maturity. It is aligned in two dimensions:
Good process assessments do this based on industry best practices. There are several frameworks or standards available to be used, for instance CMMI or Six Sigma. The one I’d like to recommend for IT Service Management, however, is TIPA.