Humans Are Terrible Estimators – How To Make Better Time Estimates

Hours in Reality / Hours in Prediction = 1.5/1 = 1.5

Reading time: 2 min

How often do you underestimate the time required to complete something?

Our ability to make time estimations is terrible.

From how much time we require to complete a task, to how much energy we consume, we tend to be way off from reality.

One study asked students to estimate how long it would take them to finish a paper under:

• realistic conditions (the best realistic estimate),
• perfect conditions (“everything went as well as it possibly could”), and
• worst possible conditions (“everything went as poorly as it possibly could”).

Their realistic condition estimates are much closer to “perfect condition” estimates than their “worst possible condition” estimates.

Moreover, not even half of the students finished their papers under their worst possible condition time estimates.

See the original study here, by Buehler, R., Griffin, D., & Ross, M. (1994).

What can we do about this, and how can we use this to our advantage?

Well, limiting time allocation in estimates does have benefits; this leverages Parkinson's Law (work expands to fill the time allocated). We tend to be more efficient when given