Project Management Primer #2 - Scope Triangle
Called the ‘Scope Triangle’ or the
‘Quality Triangle’ this shows the trade-offs inherent in any project.
The triangle illustrates the
relationship between three primary forces in a project.
Time is the available
time to deliver the project, cost represents the amount of money or resources
available and quality represents the “fit-to-purpose” that the project must
achieve to be a success.
The normal situation is that one of
these factors is fixed and the other two will vary in inverse proportion to each
other. For example “Time” is often fixed and the “Quality” of the end product
will depend on the “Cost” or resources available. Similarly if you are working
to a fixed level of “Quality” then the “Cost” of the project will largely be
dependent upon the “Time” available (if you have longer you can do it with fewer
A phenomenon known as “scope creep” can
be linked to the triangle too. Scope creep is the almost unstoppable tendency a
project has to accumulate new functionality. Some scope creep is inevitable
since, early on your project will be poorly defined and will need to evolve. A
large amount of scope creep however can be disastrous.
When the scope starts to creep, new
functionality must be added to cover the increased scope. This is represented by
the quality arm of the triangle, representing the ability of the ‘product’ to
fulfil users’ requirements. More requirements fulfilled = a better quality
In this situation you have three
1. Add time – delay the project to give
you more time to add the functionality
2. Add cost – recruit, hire or acquire
more people to do the extra work
3. Cut quality – trade off some
non-essential requirements for the new requirements
If the art of management lies in making
decisions, then the art of project management lies in making decisions quickly!
When faced with scope creep you cannot ignore it. You need to tackle it in one
of the ways described above (more later) and the sooner the better. Delaying
raises the risk of your project failing.
A poor project manager will see the
scope triangle as a strait-jacket by which their project is irrevocably
A better project manager will make better use of one or more of the
axes and will shift the emphasis in the project to one of the other axes. The
best project managers will juggle all three like hot potatoes and will make
decisions every day which effectively trade-off time versus quality versus