Programmatic Success: The system came in on time, on budget.
Technical Success: The system advanced the state of the art.
Operational Success: The system was available when needed and effective when used.
Project leaders will make very different decisions depending on which of these three they're aiming for. Of course we could aspire to succeed in all three dimensions, but all too often we settle for just the first two, or (even worse) just the first one. That’s a shame, because I think Operational Success is the most important of the three.
See, Programmatic success is all about the program manager's performance & self-interest. Technical success is all about the technologist's desires. But Operational success is about the end user's needs, and that’s the whole point, isn’t it?
I recently expanded the definition of Operational Success a bit, and now define it this way: affordable systems that are available when needed and effective when used. Note that “available and affordable” is not necessarily the same as “on time, on budget.” It’s a subtle difference, I admit, but I think the fact that the thing is ready for use when we need it, at a price we can afford to pay, is more important than whether or not we met the planned cost and schedule.
How about you? How do you define project success?