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Niels van Reijmersdal
Niels van Reijmersdal
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I think the main reason is because it easier to estimate in relative sizes. This is smaller or larger compared to that. If you look at different buildings from a distance, you could say that one is twice as large, but getting the exact height correct is much harder. For Agile work this means, if that took 2 days, this other thing of similair complexity will take probably also take 2 days.

The second reason is that estimating in hours has the risk of not taking slack and uncertainties into account. Saying a batch of work takes 8 hours does not mean it will be finished in a single day. Probably it will take two days, because noone works effectively for 8 hours, but the project manager already sold the estimate to the client who expected it yesterday. The larger the estimate the higher the risks.

Now why use Fibonacci? The Fibonacci sequence is a natural size, most things in nature hashave these relative steps. So the brain is already used to these ratios, because they are everywhere. For example, the bones in your hands follow this pattern., but also leafs, shells, etc

I think the main reason is because it easier to estimate in relative sizes. This is smaller or larger compared to that. If you look at different buildings from a distance, you could say that one is twice as large, but getting the exact height correct is much harder. For Agile work this means, if that took 2 days, this other thing of similair complexity will take probably also take 2 days.

The second reason is that estimating in hours has the risk of not taking slack and uncertainties into account. Saying a batch of work takes 8 hours does not mean it will be finished in a single day. Probably it will take two days, because noone works effectively for 8 hours, but the project manager already sold the estimate to the client who expected it yesterday. The larger the estimate the higher the risks.

Now why use Fibonacci? The Fibonacci sequence is a natural size, most things in nature has these steps. So the brain is already used to these ratios, because they are everywhere. For example, the bones in your hands follow this pattern.

I think the main reason is because it easier to estimate in relative sizes. This is smaller or larger compared to that. If you look at different buildings from a distance, you could say that one is twice as large, but getting the exact height correct is much harder. For Agile work this means, if that took 2 days, this other thing of similair complexity will take probably also take 2 days.

The second reason is that estimating in hours has the risk of not taking slack and uncertainties into account. Saying a batch of work takes 8 hours does not mean it will be finished in a single day. Probably it will take two days, because noone works effectively for 8 hours, but the project manager already sold the estimate to the client who expected it yesterday. The larger the estimate the higher the risks.

Now why use Fibonacci? The Fibonacci sequence is a natural size, most things in nature have these relative steps. So the brain is already used to these ratios, because they are everywhere. For example, the bones in your hands follow this pattern, but also leafs, shells, etc

Source Link
Niels van Reijmersdal
Niels van Reijmersdal
  • 32.6k
  • 4
  • 59
  • 125

I think the main reason is because it easier to estimate in relative sizes. This is smaller or larger compared to that. If you look at different buildings from a distance, you could say that one is twice as large, but getting the exact height correct is much harder. For Agile work this means, if that took 2 days, this other thing of similair complexity will take probably also take 2 days.

The second reason is that estimating in hours has the risk of not taking slack and uncertainties into account. Saying a batch of work takes 8 hours does not mean it will be finished in a single day. Probably it will take two days, because noone works effectively for 8 hours, but the project manager already sold the estimate to the client who expected it yesterday. The larger the estimate the higher the risks.

Now why use Fibonacci? The Fibonacci sequence is a natural size, most things in nature has these steps. So the brain is already used to these ratios, because they are everywhere. For example, the bones in your hands follow this pattern.