A recent study by social psychologist Dr. Mario Weick shows that people who are in charge – those who set policy and decide on courses of action – make time predictions that are inaccurate and overly optimistic. Why?
“The more people focus on what they want to achieve, the more they tend to neglect impediments, previous experiences and task subcomponents that are not readily apparent,” Dr. Weick explains. “Power tends to increase people's focus on intended outcomes. Although this can be beneficial, in the context of time planning we reasoned that power would lead to greater error in forecasts.”
It isn’t because people have greater faith in their abilities or that they see things through rose-colored glasses, either. “…Power affects what people focus on when they plan the future,” Dr. Weick says, “and this seems to be the root of the greater bias in powerful individuals' time predictions.'
The problem with planning and estimating doesn’t end with developers or those in charge. People in general tend to underestimate task-completion times. It’s known as the planning fallacy. A study conducted in 1994 involving demonstrated that the students did a terrible job of estimating how long it would take for them to finish their senior theses.
When it comes to software projects, estimates are regarded as poor, and industry evidence supports this. The Standish Group’s periodic Chaos Report is a widely quoted source. The statistics appear grim:
- Average cost overrun: 45%
- Schedule overrun: 63%
- Actual functionality delivered: 67%
- Because trying to predict an end date at the beginning of the project is begging for trouble. There is too much uncertainty involved.
- Mistaking estimates for commitments. An estimate is supposed to be an approximation and not a precise figure.
- Software development is a people-intensive endeavor, and people introduce a high degree of variability into the equation. The complex interactions and dynamics of the personalities involved cannot be captured in an estimate.
- Everything isn’t known by everyone up front. There is a great deal of learning going on throughout the course of the project.
DevelopersEveryone tends to be overly optimistic.