I struggle with some interpretations of the model. Some visualizations says that no projects live in the middle of the triangle. But I wonder why? It would mean that the project is of moderate quality, will be deliver in moderate time and with moderate costs. It would not be efficient as we could possibly do better with focusing on two but why is that considered utopia?

In addition, some say it is about sides, some say it is about vertices. I get that - the closer to the vertex, the better for given constraint. It does not really work with sides.

I think they are probably two views as in some, quality is the area of the triangle. But as shown in the figure here, the point represents the combinations.

5 Answers 5


Some visualizations says that no projects live in the middle of the triangle. But I wonder why?

Projects can live in the middle of the triangle, but typically there is going to be one (or two) drivers that are stronger than the other/s which is why the question tends to be posed "Which are more important in this instance?".

The theory is if you're creating a product that is "in the middle" then you're probably going to get beaten by other products in all areas. You'll be beaten on price by the low cost option, beaten on quality by the high quality option, and beaten to the market by the short TTL option.

The reason that the push is to focus on two is more about identifying the one you're not focusing on, and therefore you're identifying your area of sacrifice. When your project is under the squeeze and you have to make a sacrifice, which will it be, Cost, Quality or Time? There is always at least one area that needs to slide to accommodate for the others. Identifying that is the major purpose behind this triangle.


I don't recognise that interpretation of the model and it doesn't seem to make sense to me. For example if you start at the "Low Cost" corner and move to the right you are saying, effectively, "it will cost more and more as you move to the right but you will deliver it quicker and quicker"...

The point of the triangle, in my view, is to highlight the relationship between three critical "levers"; Time, Cost and Quality. Where your project "sits" within the triangle (yes, including in the middle), demonstrates the appetite of the project board, or the sponsor, or the company etc. to assign relative importance to the levers.

For example, if your project is right against the Cost corner, then it is saying that sticking to budget is the absolute most important lever. The relationship of the corners of the triangle means that if you absolutely prioritise one of the corners over the others you must, by definition, deprioritise the other corners. In practise, if you must stick to the budget against all the odds, you cannot also enforce rigid compliance with timescale or quality metrics.

If you absolutely must stick to a timescale, then you cannot restrict the budget or the quality and if you prioritise Quality as paramount then you cannot restrict the budget or the timescale.

In the real world, projects exist within environments that comprise a mixture of priorities of these three levers- rarely is one of them at 100% (meaning the others must be zero) so the dot representing that project would live somewhere within the boundary of the triangle. This is entirely normal.

If you ascribe other meanings to the corners then the meanings will change, but I believe what I have described is the classic Project Management meaning of the triangle.


I believe I agree with the others, but I'll put it a little differently. The Iron Triangle is about your project. The only way for a project to be "in the middle" would be if you decided to do a half effort job. (Note that if you decide that working only 40 hours a week is a prudent choice to maintain a better work life balance, that is not a half effort job; that is recognizing a constraint).

The Iron Triangle is about constraints - you can't go outside the triangle because to do so would be to violate a constraint. If you increase the speed then you're going to have to either decrease quality or increase cost. It is not a tool to compare two projects (there are far superior tools for that). It would make no sense to compare my cost/quality/speed to someone elses - they have a different set of constraints. Perhaps I have the best team in the world, but they have a nearly infinite team of nearly negligible skill; the net result is that both of us can produce at the same rate, but we'll have different implication for quality. Or perhaps they have the finances of a state actor, while I have only my own wallet but a genius idea. Comparison is not useful.

The only lesson from the iron triangle is the obvious lesson; it isn't a subtle tool, nor is it intended to be a precise tool. It is a metaphor; like most metaphors, once you understand the concept that the metaphor is pointing at, discard the metaphor and work with the concept.


I think there are more variations of the triangle. This one shows possible combinations of these three constraints.

This view helps with prioritization and stakeholder perceptions of individual constraints, as shown in the picture below:

enter image description here

In this example all participants agreed that quality was more important than cost for this process........ but there was disagreement about whether quality was more important than time. Following discussion the group finally agreed that time was more important the quality, and time and quality were more important than cost. This agreement then allows the process to be organised and run to those priorities with common understanding.

I think the following picture provides a better understanding and maybe clarifies what @Marv Mills thought did not make sense but actually it is perfectly logical to me: the further you go from the "Cost" corner, the more you are willing to spend in exchange for faster delivery. You can either have a cheap product after a long time or you can have it fast but it will be expensive.

enter image description here


This was talked about while I was at university. Rather than the areas within the triangle relating to whether or not it is more spend, or more time, or better quality (as if on a sliding scale, akin to the examples provided previously), it is sustainability that exists in the middle.

It's used as a reminder for you and your stakeholders to consider how sustainable your method and solution is.

For example:

For the method, it could be understanding if it is sustainable for your business/client to continue spending at the rate they are? Using the current rate of work are we able to maintain the quality of the solution? Etc.....

For the solution, will this be fit for purpose in a years time? Will we make a good ROI? Does this meet/exceed all known legal requirements? Etc...

By doing this, you can help work towards making sure that your project has been properly understood and validated by the business and the solution that is being created has a full lifecycle.

There are other schools of thought where the triangle should be scrapped for a shape with more points.

However it is used, the iron triangle is a handy tool.

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