Glossary Category:

⌊example quantification Gilb⌋

A representation of multiple performance and resource attributes showing goal and budget levels respectively. The ‘point’ of the icon goal and budget symbols indicates the level (reference needs to be made to the Scale to interpret the numeric value). One constraint, a Fail level, is shown on the resource attribute for Financial Budget [Stakeholder A]. The lines of the arrows represent the scales of measure (divisions along the scales are also marked).

From: Competitive Engineering 2005 – Tom Gilb



INCOSE Systems Engineering Handbook 2015

This handbook defines the discipline and practice of systems engineering (SE) for students and practicing professionals alike and provides an authoritative reference to understand the SE discipline in terms of content and practice.


NASA Systems Engineering Handbook 2020

This handbook is intended to provide general guidance and information on systems engineering that will be useful to the NASA community. It provides a generic description of Systems Engineering (SE) as it should be applied throughout NASA. A goal of the handbook is to increase awareness and consistency across the Agency and advance the practice of SE. This handbook provides perspectives relevant to NASA and data particular to NASA.

This handbook should be used as a companion for implementing NPR 7123.1, Systems Engineering Processes and Requirements, as well as the Center specific handbooks and directives developed for implementing systems engineering at NASA. It provides a companion reference book for the various systems engineering-related training being offered under NASA’s auspices.


A Requirement specifies a System (Element)’s desired characteristic, quality, function aspect or behavior in defined circumstances under specific  conditions.