The study noted:
Interestingly, people often underestimate the time it takes to accomplish tasks. This bias is known as the planning fallacy and derives from a too-narrow focus on the envisaged goal. 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. As a result, time predictions are often inaccurate and too optimistic. 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.
The big picture? It seems high-up workers — like managers — have more faith in their abilities than those who are less empowered. I'm sold on these findings. Who hasn't been overly confident about their super speed or had a boss bark orders about how easy and quick a project should be?