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Using Expert Opinion in Grassroots Cost Estimation

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Bill Taber

Dan Port

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Consulting the Experts

  • Seasoned software engineers can gage the difficulty of performing some task in the software domain.
  • They can give you an honest estimate about how long it will take them implement it.
  • Their estimate will be wrong.

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  • That doesn’t mean their estimate is without value

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Weber-Flechner Law

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The Law of Ratios

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Evidence

  • Since 2010, the Monte development effort at JPL has been recording estimates and actuals for effort to implement new features in the system.
  • The empirical distribution certainly looks exponential

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Evidence:

 

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Statistical Consistency

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Komogorov-Smirnov Test

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Consequences

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More Consequences

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Application

  • It’s relatively straight forward to instrument an Excel Workbook to utilize this idea.
  • Enables real-time negotiation with stakeholders when planning what’s in and what’s out of the next release.

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Possible Applications to COCOMO

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