Estimates vs. Targets
On Monday I attended an Executive Breakfast put on by Construx Software. Steve McConnell, renowned author of books like Code Complete and also one of our advisors, discussed the “10 Deadly Sins of Software Estimation.” Not surprisingly, most of the audience chuckled knowingly after each “sin” was read aloud. And even as one of the few non-developers at LiquidPlanner, I found many parallels to the stuff that goes on in marketing projects I work on.
The very first sin actually struck quite a chord: Confusing Estimates with Targets. It’s not uncommon that people use the word “estimate” when they really mean “target,” or maybe even “commitment.” Here’s the kind of dialogue that goes on quite often in project meetings.
Project Manager: “Chris, how long do you think it will take you to make that change?”
Chris: (on the spot) “Umm. Hmm. Maybe four days? Maybe six?”
Project Manager: (scribbling away) “Great, gotcha. So Tim, how long will it take you…..”
Wanna bet that the PM wrote down four days next to that task? Wanna bet that Chris didn’t really think about what he might be signing up for when he “estimated” that task?
Say you have a project that needs to be completed by June 1st — that’s your target date. What do you do next? Do you create a work breakdown structure, estimate your tasks, and hold your breath that the schedule says you’ll finish on time? If not, do you go back in and reduce all your estimates, just so your dates match up?
That kind of habit seems to be a pretty clear recipe for failure. By clearly separating estimates from targets or commitments in your project plan, you can set expectations up and down the chain. If your schedule says you’ll run over, you can have a real conversation about cutting features, adding resources, or maybe even the need to plan for overtime. (In LiquidPlanner, we use “promise dates” (denoted by the diamond symbol on your schedule) to set targets, and ranged estimates to create schedules that capture uncertainty.)
Managing project schedules is really about the iterative process of bridging the gap between the target date and the estimated completion date. Kudos to Steve for bringing to light the fact that this is more than a semantic difference.