iron triangle models constraints of project management and these constraints are
considered “iron” because you can’t change one constraint without impacting the
others. The original iron triangle, proposed by Dr. Martin Barnes in 1969,
follows a waterfall approach to product development: scope is fixed and
resources and time are variable. For a software team, this would mean that teams
start a project by defining product requirements to determine a project’s scope
(a list of work items). The resources and schedule are variable and are
estimated depending on the fixed scope.
