One of the first project management concepts that I learned was the time, cost, quality triangle. I was
given the task of managing a conference and I was trying to find a way to express a common challenge. The
conference date was fixed. There simply weren't enough days to write, design and print the completed
full-colour training materials.
Table of Contents
The Triangle of Objectives
In the mid 1980s Dr Martin Barnes created the Triangle of Objectives. The triangle demonstrates that
quality cost and time are interrelated. Focussing or fixing one point of the triangle impacts the other
two (Lock, 2007, p21).
How I solved the conference problem
In the case of the conference a trade off had to be made in quality or cost to meet the fixed date. In
the end the printing was changed from colour to black and white and drafts were sent to the first day
with final versions arriving on the third day.
Dr Barnes later updated the triangle to performance, cost and time as he felt that quality implied
little more than compliance with specifications.
Dennis Lock points out that many more deriviations of the triangle have since been developed (2007,
p22). My perception is that the most often seen variation is to replace performance or quality with
scope
. In my opinion this is a calculated attempt to insist that compliance to spec is - as Barnes tried to
avoid - all that is required. This is perhaps partly the cause of common complaints that waterfall
methods are inflexible, assume fixed requirements and are resistant to change.
Common variations of the project triangle
This version places quality in the centre, making a clear distinction between
scope
and quality. Here
scope
is the deliverables and specification, but quality has moved to centre, so that any change to any
side affects quality (office.microsoft.com, 2014).
Kliem and Ludin modified the triangle of objectives to show people at the centre. They called this
The Four Variables of Project Success.
if people are not considered a crucial element, the project will fail, even in the presence of
good plans, organizational structure, and proper controls (Kliem, Ludin and Robertson, 1997,
p24).
Lock proposed a combined version of Barnes's original with Kliem and Ludin's, but replaced 'quality'
with 'level of specification'. Arguing that if quality is defined as 'fit for purpose' it can never
be negotiable. 'Performance' or 'Level of specification is more appropriate because that can be
negotiated (Lock, 2007, p22).
How to use the triangle
Decide at the start of a project which version of the triangle you will use and agree with the
project sponsor
which of the three or four objectives are most important. Assess changes, risks and issues against the
triangle and weigh up your course of action against the impact on the critical objective.
Project Management Triangles
The Iron Triangle can help with
Managing expectations
and more..... it drives the project direction
Project approach
Dig by hand
1
2
3
4
5
6
7
Excavate
Pour
1d
Cure
1d
Build
3d
Use an excavator
1
2
3
4
5
6
7
Excavate
Pour
1d
Cure
1d
Build
3d
The project could be completed one day earlier by using an excavator, but what if the cost is
fixed?
Changes to scope
You have a change request to:
Add a custom widget to improve customer experience.
Click to fix each part of the triangle & see how that impacts your decision
Staffing decisions
The tick shows quality, the alarm clock shows time, and the dollar sign shows cost.
Engineer 1
10 years’ experience
£1,000 per day
Fully certified
All skills required
One month’s notice
Quality
Green
Time
Red
Cost
Red
Meets the quality requirements, but has the longest notice period and highest daily
rate.
Engineer 2
2 years’ experience
£700 per day
Partly certified
All skills required
One week’s notice
Quality
Amber
Time
Green
Cost
Amber
Certification needs checking. Available sooner, with a mid-range daily rate.
Engineer 3
Newly qualified
£500 per day
Missing ACME CERT
Available immediately
Quality
Red
Time
Green
Cost
Green
Available immediately at the lowest daily rate, but missing ACME certification.
In this example:
green = suitable; amber = needs checking; red = a concern.
Try the Iron Triangle Explorer
Put the ideas into practice with an interactive CRM project.
Change the team and first-release features to explore
the effects on time and cost.
According to Andy Oppel some claim that the concept of three interelated objectives comes from Hollywood
where producers manage the interelated objectives/aspiration of a quality film, produced quickly on
small budget (2009).
