The next piece of software is to be developed as quickly as possible by two teams and they now have to answer how long it’s going to take. Team A says 5-8 months and Team B 6-9 months. But the department head is under pressure to give a date. He decides to simply take 7 months as the average of the two teams and so the rest of the project plan ends up based on averages. Basing on the book "The Flaw of Averages," this presentation explains why average-based plans fail on average and provides a way to avoid this trap at least when it comes to software development estimates.
15. Whenever an average is used to
represent an uncertain quantity, it
disturbs the results because
it ignores the impact of the inevitable
variations
#CodemotionRome19 @DaianyMargarita
16. We need to act on a
distribution
rather than on
single
values
#CodemotionRome19 @DaianyMargarita
29. #CodemotionRome19 @DaianyMargarita
We avoid
the trap of
averages
We provide a
more realistic
forecast
We reduce
the waste
of time
We keep a
better eye on
the course of
the team
Some benefits we have from
#ContinuousForecasting
31. #CodemotionRome19 @DaianyMargarita
The Trap of Averages
How to avoid it in software development estimates
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WHAT IS THE PROBLEM?
Plans based on average fail on average, because they ignore the impact of variations.
Well-considered projects are doomed to disappointing results.
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WHAT TO DO?
Act on a distribution of values and their likelihood of happening, instead of using
single values (an average).
HOW TO DO THAT?
Use a Monte Carlo Simulation for a probabilistic forecast based on historical data.
Adopt a Continuous Forecasting strategy.
WHAT ARE THE BENEFITS?
Chances of hitting the estimated date are increased. Waste of time is reduced.
The team can use its precious time to build awesome things instead!