The Triple Constraint
Time, Cost and Scope
Last updated
Time, Cost and Scope
Last updated
The 3 factors in project management. Any adjustment to one of them affects the other two. We must carefully navigate these constraints to achieve project success. To put it super simple
Cost: The total number of engineers
Scope: A list of features
Time: Deadline
Does that mean a project manager can play with all 3 factors? The answer is a clear no. Most of the time, there is at least one factor you can't change, the trade-off is mostly between the rest 2 feasible constraints
Imagine a high-performing cross-functional team where members know each other well, fostering excellent communication. What does their triangle look like?
Normally fixed, limited by headcount, and budget. Compete with other priorities. Importantly, increasing developers doesn’t necessarily boost productivity and adding a new member to a high-performing team can slow them down.
The scope of the project is negotiable. At the discovery stage, we just have a list of features we would like to deliver, but some are must-haves and the rest are nice-to-haves. So in an agile team, we normally prioritise features and put them in sequence. For example
MVP: Feature A, B, C
Fast Follow: Feature X & Y, and optimising feature A
Settle Down: Code clean up or address some technical debt
Imagine a consultant company with a large talent pool. They are able to form a team and get stuff done quickly. What does their triangle look like?
Negotiable, but once agreed, it becomes the agreement between the two parties.
Based on estimation. It is very challenging. People write books to express how hard it can be.
Some quotes from The Mythical Man-Month by Fred Brooks in 1975.
PS: Man=Cost and Month=Time
Adding manpower to a late software project, makes it later
For the human makers of things, the incompletenesses and inconsistencies of our ideas become clear only during implementation
Men and months are interchangeable commodities only when a task can be partitioned among many workers with no communication among them
How does a project get to be a year late? . . . . One day at a time
