Leading source for the performance qualities of the Systems Engineering activities is G. Roedler, D.H. Rhodes, H. Schimmoller & C. Jones, “Systems Engineering Leading Indicators Guide” LAI, INCOSE, PSM and SEAri, INCOSE Technical Product Number: INCOSE-TP-2005-001-03 Version 2.0 (2010). Accessed on September 10th, 2020 here.
As with any method there needs to be a clear set of requirements that it needs to address. Below requirements are borrowed from D. Long & Z, Scott “A Primer for Model-Based System Engineering”, Vitech Corporation, 2nd edition (2011). I've only replaced 'process' with 'methodology' to broaden the scope as well as replaced 'must' with 'shall' to make it consistent with standard requirements terminology. Requirement 5, regarding tailoring, is my own addition.
Requirement 1: The methodology shall consistently lead to the development of successful systems
Requirement 2: The methodology shall manage system complexity well
Requirement 3: The methodology shall lead to effective solutions to a broad range of customer needs
Requirement 4: The methodology shall accommodate three main problem classes (engineering unprecedented systems, reverse engineering, and engineering precedented systems)
Requirement 5: The methodology shall allow for tailoring to adapt to particular risk profile and project constraints
J. Martin proposed in Martin, J. 2004. “The Seven Samurai of Systems Engineering: Dealing with the Complexity of 7 Interrelated Systems.” Proceedings of the International Council on Systems Engineering (INCOSE) International Symposium, 2004, Toulouse, France that there exists seven systems in the design space.
Above figure is from a presentation given by J. Martin in 2012.
These are:
Context System
Intervening System (“as-designed” system)
Realization System (e.g. design teams, production systems)
Deployed System (“as-built” system)
Collaborating System (e.g. external systems)
Sustainment System (e.g. maintenance)
Competing System
Interactions between the systems are
Context System contains Problem
Intervening System is intended to address Problem
Realization System brings Intervening System into being
Intervening System is a part of Realization System
Realization System needs to understand Context System
Realization System needs to understand the Modified Context System
Realization System may need to develop or modify the Sustainment System
Intervening System becomes Deployed System
Context System becomes the Modified Context System
Deployed System is contained in Modified Context System
Deployed System interacts with one or more Collaborating Systems
Deployed System is sustained by Sustainment System
Deployed System may cause new Problem
Competing System(s) may address the original Problem
Competing System(s) compete with Deployed System for resources and for the attention of users and operators