The Iron Triangle. Is it Broken? + CHEAT SHEET

Episode 80 - 12 Apr 2017

Last time, we looked at the Iron Triangle. This time, I'd planned to move on to a different subject. And then I received this question from RaxDaMan:

"If you want to have it good and cheap, how making it longer helps? How making project longer, makes it cheaper? Never got it really :)"

More time means more cost, right? Could it be that the Iron Triangle is BROKEN?

Oh, and be sure to grab your copy of the "Waterfall vs. Agile Cheat Sheet".

Previously, we looked at the Iron Triangle.

Today I planned to move on to a new subject.

But then a question came in that really had me scratching my head.

And this is the question that spoiled my week:

"If you want good and cheap, how does making the project longer help?"

RaxDaMan, thank you so much for your question.

I think this is the clip you were referring to:

"I can do Fast, Good, and Cheap. Which TWO would you like?"

  • Cheap and Fast ... rush the the job and the Quality will suffer

  • Cheap and Good... is going to take time

  • Fast and Good - which might mean putting more people on the job - will push the price up.

I confess that when I was putting together last week's episode, it was this case - the case where cost and quality/scope are fixed - that didn't sit right with me.

My first thought was to blame the model: cost and time are not independent.

But then I realised that the Iron Triangle is composed entirely of parameters that are INTER-dependent.

Let's make sure I'm interpreting the model correctly:

  • We can fix one parameter
  • We can fix a second parameter
  • But we can never fix a third.

When we fix two parameters, we're saying that this one must be allowed to CHANGE.

Last time I strongly implied the direction of the change. But change in the opposite direction is also possible. We'll see an example of that in a moment.

For my next trick I'm going to bring back the decorator. And introduce a client.

They have come to a shared expectation about the quality/scope: Quality/scope is fixed.

They've also agree to do the project on a Fixed Price Basis.

Does that mean the cost is fixed?

Well, it means that the client's cost is fixed.

What about the decorator's costs?

Well, one way or another, the decorator has estimated the cost for the job.

He might estimate that it will take hime a week... and price the job accordingly.

Assuming that he's a sole trader, there are three possible outcomes:

  1. He does the job in 5 days as expected
  2. he gets the job gets done in 4 days
  3. He runs into difficulties and the job takes 7 days.

I think it's true to say that from the decorator's point of view, the quality/scope is the only thing that's fixed.

In each of the cases we just looked at, cost and time are different. But from the client's point of view, quality/scope and cost are both fixed.

One project, two people, two different views of the Iron Triangle.

Waterfall vs Agile Cheat Sheet

The Iron Triangle is just one element of the "Waterfall vs Agile Cheat Sheet".

If you've yet to grab a copy, you'll find a link somewhere around this video. Click the link, follow the instructions. and it's all yours.