How To Fix Martin Fowler's Estimating Problem in 3 Easy Steps

Hosszú, de érdekes.

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When asked to produce or handed an estimate, respond with the following:

• What confidence level are you needing for the estimate you’re asking us to do?
• What confidence level have you assign to those estimates you handed me?
• What is the shape of the Probability Distribution for those estimates you want me to use?

Here’s how to fix this

• Look to similar past performance work to see if we can extract classes of work that can be used as the basis of estimating the new work.
• Better yet, go cobble together a walking skeleton to see if we can build our own reference class.
• DO NOT GUESS, use agile to find out before we proceed.
• Assign a confidence interval to all the estimates so we can determine where the problem children are and record that confidence for later.

Second Bullet

Using estimates during development

Here’s how to fix this

• When those statistically acceptable set of estimates are arrived at, make them part of the release plan. And make sure their confidence intervals are publicly visible and can’t be ignored - the BIG VISIBLE CHART is one way.
• Color coding can work. Standard Deviations from the Mean can work. Anything can work as long as it is recorded in the plan, agreed to by the team - remember those agreement processes we did when we formed the agile team.
• Revisit those confidence intervals and the Most Likely † value for the estimate every time we release something, start to work on the next release, or do anything that impacts our confidence in the estimates.

Third Bullet

Here’s How to Fix This

• Actuals HAVE to be different than the estimate. That’s why it’s call an ESTIMATE
• An estimate is an indication of the value of an unknown quantity based on observed data or a model of the possible values that would be observed.
• Adjust those estimates for actual work. Adjust them for anything and everything that impacts the work.

Estimating the furture is not about controlling the future, it’s about being prepared to respond to the emerging possibilities of the future

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Never use average or allow anyone to speak to us about the average.

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