What critical lesson have I learned about the process of making an estimate?
Have your most pragmatic, experienced people do the estimate.
Minimize the number of people who are members of the estimating team. A team size of three, in my experience, is ideal. That’s enough members to trigger divergent estimates, which creates arguments, which leads to better estimates. And it’s also a team size that converges without the pain that happens too often with larger teams.
If your organization’s management demands that inexperienced people attend the estimation meetings so they learn how to estimate, have each of these attendees wear a baseball hat with Observer labeled on its front panel. Make it clear to the observers that they are only to observe the process rather than to participate. The hats are symbolic and will remind you and them of their role as observers.
Why? Inexperienced people may not know what the don’t know, which will slow down the estimation process without increasing the quality of the estimate.
For instance, I was a participant in an exercise at a workshop where we were ask to order estimated times for a series of a kitchen remodel tasks, such as changing the electrical wiring, adding granite countertops, and adding hardwood floors.
A few of us in the group had experience either doing the work or contracting the work. The majority of the people in the group had zero experience, but a few of them didn’t want to opt out of the experience. They wanted to learn the process, which was laudable. But by participating, the inexperienced people only slowed down the experienced people. Again and again, I heard, “it shouldn’t take that long…”
I felt bad telling the inexperience people they weren’t helping, but I it was true. Meaningful participation happens when someone brings something to the table that furthers the process.
Don’t ensnare yourself in the web of other people’s inexperience. Insist that only pragmatic, experienced people do the estimation task. If you only have a single person with the proper credentials, let him or her make the estimate.
Inexperienced people: What happens when the people who would actually have to perform the task are those inexperienced folks – what does that mean for the educated estimates?…
Hi Arnon,
Don’t Hide the Estimate’s Variability.
The forecast from an inexperienced IT person are typically worse than the forecasts of an inexperienced meteorologist. Why? The forecasts of meteorologists are grounded in probability. They talk about the chance of rain rather than saying it will rain tomorrow. Inexperienced IT people typically use point estimates, such as, “We will deliver on August 2nd,” which prevents their customers from seeing the inherent variability of an estimate.
Meteorologists are also trained on how to forecast while IT people, in my experience, typically receive little training on estimation. And if they do receive training, their company’s culture may prevent them from practicing what they learn.
Meteorologists also have data and models to aid their predictions. IT people, in my experience, rarely have data about previous projects and typically have zero models for making estimates.
I believe estimation is an art as well as a science. People need experience in order to make solid estimates.
If inexperienced people must make the estimate, I suggest avoiding point estimates entirely. Like a meteorologist, create a probability based forecast. I like a graph with the x-axis being time and the cumulative probability of delivery on the y-axis. The graph is dynamic rather than static. As you learn more, the probability change.
I’ve notice that many groups are afraid to share their uncertainty with their customers until they must. I don’t recommend that approach. But if, for whatever reason, you must hide the estimate’s variability from your customer, that doesn’t stop you from making it visible internally.
You learn to be a better estimator by practicing. If you hide the variability from yourself, it’s poor practice.
Thank you for the question. And I wish you and your group success with your efforts.
Best regards,
-Steve
Arnon,
I suspect you already know.
I looked at your website, which I now wish I would have looked at before my first reply. I see you are very experienced.
I suspect you have experience about happens when inexperienced people make estimates.
My experience is that inexperienced people do their best when making estimates. Unfortunately, they tend to underestimate.
I don’t think anyone should be surprised.
Warm regards,
-Steve
rather…
People who will do the work should do the estimation as well.