Jacob Kaplan-Moss begins where I often do when discussing estimation:

One study by HBR found that one in six IT projects had cost overruns of over 200% and were late by almost 70%. Another study by McKinsey found that IT projects are on average 45% over budget and 7% over schedule. They found large software projects were particularly bad: software projects with budgets over $15M went over budget by an overage of 66% and had schedule overruns averaging 33%.

Nonetheless, there are good reasons to estimate anyhow… and you can get better at it over time.

One major “secret” to advancing in a technical career is learning how to give accurate estimates. It certainly has been for me: I don’t shy away from giving timelines, and I’ve learned how to be right often enough that folks trust my estimates.

If you always avoid estimation and don’t learn how to give a timeline when it’s required, that might become a limiter on your career. Being able to tell your bosses and peers what to expect by when – and then hitting those marks – builds trust in a major way.

If you like this post, maybe follow it up with the one where he covers his technique for estimation.