A Gross Oversimplification

Every software developer has heard it: “How long do you think that will take?” And they are expected to respond with a single duration, to which they will be held accountable. This ignores uncertainty.

For many professions, the uncertainty is small enough that reasonable predictions can be provided. For example, a carpenter might tell you that he’ll take 2 weeks to build a fence. He doesn’t know that exactly, but he’s pretty sure:

With this little uncertainty, a single duration suffices.

Let’s look at some software development curves. I would guess most tasks look something like this (“I think that will take 2 weeks, but perhaps longer”):

Well that’s a different picture. What is the single duration here? 2 weeks? 4 weeks? There is a lot of uncertainty, and a single number is a gross oversimplification.

There are many different graphs that software developers might be trying to say.

“I’ve done that before, it’ll take max 2 weeks but I might find a shorter way”:

“That will either be really easy, or it could be a lot of work”:

And the carpenter case: “That will take about 2 weeks, I’m sure of it”:

Single numbers simply cannot describe these scenarios.

At a sprint planning meeting, have all the teammates independently draw their own probability distributions for a task estimation, and then compare. How uncertain are you about your uncertainty?

Related posts:

A contract research organization (CRO) is a company that provides support to pharmaceutical and biotechnology companies in the form of research services outsourced on a contract basis. CROs offer a…

Kids love to be surrounded by colourful objects that can give their imagination meaning. Wall painting using vivid colours is fun however it is essential to have a theme in mind and add colours to…