How Long Will This Take? 3 Steps to Being a Better Judge of Time

People 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.


Every Saturday morning, while my
husband is eating his cereal and attempting to fully awaken, I ambush him
with the list of household chores and errands I’ve been making all week (and
saving for when he’ll be home to help me.) Every single time, an argument ensues. At its core is his unshakeable belief
that any task, no matter how complex or difficult, can be completed in about 15
minutes. “Let’s go out and have
some fun, ” he’ll say, “and we’ll tackle that stuff when we get back this afternoon.” “But there won’t be enough time!” I
reply, with mounting frustration.
“It will be fine,” he says.
More often than not, he is wrong.


As much as I enjoy giving him a
hard time about his total inability to judge how long something will take, the
truth is that most people aren’t much better at it. 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

Second, we ignore the very real possibility
that things won’t go as planned–our
future plans tend to be “best-case scenarios.”
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.

In one study, half of the student
participants were made to feel powerful (by being told that their opinion would
influence the course requirements established for future students). Next, all students were asked to
estimate how long it would take to finish an upcoming major assignment. Everyone was overly-optimistic,
but the powerful ones were significantly more
so. Powerful students estimated
that they would finish their assignments 2.5 days before they actually did,
while the control group was on average only 1.5 days late. So feeling powerful makes you think you’ll take a whole day less to complete the
assignment than you would have guessed had you been feeling a little more


A second study induced feelings of
power by having some of the participants recall a time in their past when they
felt very powerful, and this produced a similar result. Powerful participants estimated that it
would take them only 4 minutes to complete a proofreading task that actually
took 9 minutes, compared to the control group’s estimate of 6.5 minutes.

In a third study, participants who
were made to feel powerful thought it would take them less time to write an
essay, get ready for an evening out, shop at the supermarket, and prepare a 3
course meal, than the control group. Importantly, these effects completely disappeared when
powerful participants were explicitly told to recall how much time these
activities had taken them in the past, and use that information to make their
estimates. So when powerful people are forced to focus on all the relevant information, their planning is far more accurate.

When you’re making a plan and
estimating how long it will take, be sure to stop and:

1) consider how long it has taken you in the past,

2) identify the ways in which things might not go as planned, and

3) spell out all the steps you will need to take to get it done.


This is particularly important when
you are in a position of power, so make sure that there are safeguards or
reminders in place to help you to consider all
the information you should. Otherwise,
you may fall victim to the everything-takes-15-minutes kind of optimism that can
lead to disaster.

Heidi’s new book Succeed: How We Can Reach Our Goals is available wherever books are sold. Follow her on Twitter @hghalvorson.

Not sure why you aren’t reaching your goals? Take the Goal Troubleshooter Quiz.