In fact, human beings are generally pretty lousy when it comes to estimating the time they will need to complete a task. Psychologists refer to this as the planning fallacy, and it’s an all too common problem - one with the very real potential to screw up our plans and keep us from reaching our goals.
Studies show that the planning fallacy can be attributed to several different biases we have when estimating how long it will take to do just about anything. First, we routinely fail to consider our own past experiences while planning. When my husband tells me it will take him 15 minutes to vacuum the carpets, he is ignoring the fact that it took him an hour to do it last time. And as any professor can tell you, most college seniors, after four straight years of paper-writing, still can’t seem to figure out how long it will take them to write a 10-page paper. We just don’t take our past into account the way we should when thinking about our future.
Second, we ignore the very real possibility that things won’t go as planned - our future plans tend to be “best-case scenarios.” So running to the store for a new vacuum cleaner might take 15 minutes - if there is no traffic, if they carry the model we’re looking for, if we find it right away, and if there aren’t long lines at the register.
Lastly, we don’t think about all the steps or subcomponents that make up the task, and consider how long each part of the task will take. When you think about painting a room, you may picture yourself using a roller to quickly slap the paint on the walls, and think that it won’t take much time at all - neglecting to consider how you’ll first have to move or cover the furniture, tape all the fixtures and window frames, do all the edging by hand, and so on.
So while we all tend to be prone to the planning fallacy to some extent, some of us fall into its trap more often than others. People in positions of power, for example, are particularly vulnerable, because feeling powerful tends to focus us on getting what we want, ignoring the potential obstacles that stand in our way. A recent set of studies by Mario Weick and Ana Guinote shows that such a narrow focus does indeed turn powerful people into very poor planners.