The Iron Triangle (Scope, Time, Cost)
Introduction
All project planning can be done thinking of Scope, Time, and Cost. The Architect must retain the right to determine the project's level of quality based on these three things in order to assure the successful completion within the established budget.
Under no circumstance should all three of the items be fixed. One or two must always be variable and the client should understand this. When thinking about increasing the size (scope) of a project and keeping the quality the same, the cost and time will inevitably be affected. The relationship between these three should always be considered as it is a reality of construction.
"Good, fast, cheap. Choose two." - John Ruskin
Iron Triangle (Time, Cost, Scope)
The iron triangle is a management principle that refers to the relationship between Time (T), Cost (C), and Scope (S). These three things together deliver the Quality of the project you will get. To maintain quality you need to adjust the three variables.
The principle essentially states that for any project, you can only optimize two of these three constraints. For example if you want something fast and good quality, you should expect to pay more. The approach to try and excel at all three simultaneously is considered difficult and perhaps impossible at times. Adjusting one of three factors will affect the others either positively or negatively.
- For example, better quality; will generally either cost more or take more time to achieve.
- In principle it's understood that they all aren't directly related. Throwing more people at a fully staffed problem could cause it to slow down.