Estimates

Why we're bad at them and how to get better

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What is an estimate?

A forecast about the future

Weather: One of the most studied areas for prediction can only manage to predict up to 5 days out with any amount of confidence.

src: http://www.minitab.com/en-us/Published-Articles/Weather-Forecasts--Just-How-Reliable-Are-They-/

Normal Reaction of Devs asked to Estimate once they know this:

So how long will the project take?

How do we bring process (and sanity) to what is otherwise random guesses?

2 Categories

  • Break up the estimates
    • Into smaller ones (bottom-up)
    • Across to more people (consensus)
    • Into more estimates per thing (3-point)
  • Use historics
    • By comparables (analogues) 
    • By rates (parametric)
    • By estimator deviation

No "right" way to do this. Your mileage will vary.

Estimates: why we're bad at them and how to get better

By Robert Roskam

Estimates: why we're bad at them and how to get better

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