Skip to main content

How to make the classic PM Iron Triangle

Agile Tetrahedron Model
I was in a workshop just the other day and asked if everyone was aware of the dynamics of the classic project management iron triangle.  While most people had heard of it, it was apparent that few actually understood the dynamics of the model.
For a better model than the PM triangle see the Agile Tetrahedron.
Perhaps a physical model of the PM triangle would help people to grasp the meaning.  So let's build an adjustable Iron Triangle out of something.  It needs to be inexpensive, made from common items, and build-able in 20 minutes.

Here's is how to make a PM iron triangle out of plastic drinking straws.

You need:

  • Straws - the bendable kind - multi-colored.
  • Scissors
I used 3 yellow straws for the flexible corner pieces.  Cutting the straw just about 2cm beyond the flex on each side.  I cut the straw at an angle.  This makes assemble easier, as you must crimp and slide this piece into other straws.  The taper makes this easier.



Cutting diagram & finished triangle
Working on the red side.  I use 2 red straws.  Cut one into 3 pieces, throwing away the flex part.  The other is cut just to the side of the flex and throwing away the flex part also.  You are left with 3 red pieces, one short and two long.  Slide the yellow flex parts into the short red piece and the other yellow flex into one of the long red pieces.

One side of the adjustable triangle.
Repeat for the green side and the orange side.

All the pieces of the triangle
With the remaining long pieces we make the inner tubes.  Crimp the straw longitudinally so that it will become smaller and slide into the other straws.  Insert one end into the short red straw.  Do the same for the green and orange sides.
The 3 angles
 Now the angles may be assembled into a triangle.  Sliding one straw over the crimped straw.  This allows the sides to adjust in length.  And flex at the corners.

You now have an adjustable Project Manage Iron Triangle.  Label the sides and start playing with it.  Enjoy your new found understanding of the constraints of projects.

If you need an explanation of the power of the Iron Triangle and its limitations as a model for software development listen to the Agile in 3 Minutes: episode 21 Predict.


Post a Comment

Most Popular on Agile Complexification Inverter

David's notes on "Drive"

- "The Surprising Truth about what Motivates Us" by Dan Pink.

Amazon book order
What I notice first and really like is the subtle implication in the shadow of the "i" in Drive is a person taking one step in a running motion.  This brings to mind the old saying - "there is no I in TEAM".  There is however a ME in TEAM, and there is an I in DRIVE.  And when one talks about motivating a team or an individual - it all starts with - what's in it for me.

Introduction

Pink starts with an early experiment with monkeys on problem solving.  Seems the monkeys were much better problem solver's than the scientist thought they should be.  This 1949 experiment is explained as the early understanding of motivation.  At the time there were two main drivers of motivation:  biological & external influences.  Harry F. Harlow defines the third drive in a novel theory:  "The performance of the task provided intrinsic reward" (p 3).  This is Dan Pink's M…

Exercise:: Definition of Ready & Done

Assuming you are on a Scrum/Agile software development team, then one of the first 'working agreements' you have created with your team is a 'Definition of Done' - right?



Oh - you don't have a definition of what aspects a user story that is done will exhibit. Well then, you need to create a list of attributes of a done story. One way to do this would be to Google 'definition of done' ... here let me do that for you: http://tinyurl.com/3br9o6n. Then you could just use someone else's definition - there DONE!

But that would be cheating -- right? It is not the artifact - the list of done criteria, that is important for your team - it is the act of doing it for themselves, it is that shared understanding of having a debate over some of the gray areas that create a true working agreement. If some of the team believes that a story being done means that there can be no bugs found in the code - but some believe that there can be some minor issues - well, …

Team Performance Model - by Drexler and Sibbet

Many of you have all heard of the Tuckman model of team dynamics (Forming, Storming, Norming, Performing).  It was created in 1966 and has become the most popular model for describing team behavior.  Is it time to level up in your mental model of team dynamics?  Are you ready for a richer more functional model?



Introducing the Team Performance Model by Drexler and Sibbet



Orientation - Why am I here?
"Orientation is about understanding the purpose of a team and assessing what it will mean to be a member.  you need to understand the reason the team exist, what will be expected of you and how you will benefit from membership.  In a new team, these are individual concerns, because the group is only potentially a team.  that is why these concerns are illustrated as occurring in your imagination at an intuitive level.  As a team leader it is important to provide time and space for people to answer these internal questions themselves."

Keys to when Orientation challenges are resolve…

Situational Leadership II Model & Theory

Have you ever been in a situation where you thought the technique needed to move forward was one thing, yet the person leading (your leader) assumed something else was what was needed?  Did you feel misaligned, unheard, marginalized?  Would you believe that 54% of all leaders only use ONE style of leadership - regardless of the situation?  Does that one style of leading work well for the many levels of development we see on a team?

Perhaps your team should investigate one of the most widely used leadership models in the world ("used to train over 5 million managers in the world’s most respected organizations").  And it's not just for the leaders.  The training is most effective when everyone receives the training and uses the model.  The use of a ubiquitous language on your team is a collaboration accelerator.  When everyone is using the same mental model, speaking the same vernacular hours of frustration and discussion may be curtailed, and alignment achieved, outcomes …

Refactoring - examples from the book

Martin Fowler's book Refactoring:  Improving the Design of Existing Code has a simple example of a movie rental domain model, which he refactors from a less than ideal object-oriented design to a more robust OO design. Included in this Refactoring_FirstExample.zip Zip file are the Java source code files of the Movie, Rental, and Customer classes. Along with a JUnit CustomerTest class. Using these example source files you too can follow along with the refactoring that Fowler presents in the first few chapters of his book.