software prediction models forecasting the costs of software development

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Software Prediction Models Forecasting the costs of software development

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Page 1: Software Prediction Models Forecasting the costs of software development

Software Prediction Models

Forecasting the costs of software development

Page 2: Software Prediction Models Forecasting the costs of software development

Prediction Study Outcomes Vary

Estimation-by-analogy beats regression Or not Classification and regression trees (CART)

beats regression Or not Artificial neural networks beat regression Or not

Page 3: Software Prediction Models Forecasting the costs of software development

Why Are The Results Conflicting?

Poor data or research procedure Complex techniques may require expert

users; hence applications may vary Small sample size Measurement process that is flawed Selective use of differing parameters may

result in different rankings

Page 4: Software Prediction Models Forecasting the costs of software development

Key Terms

Accuracy indicator– Some measure of a process– A summary statistic based on that measure

Leave-one-out cross-validation Arbitrary function approximator taxonomy

– Many-data versus sparse-data– Linear versus nonlinear– Supervised versus unsupervised

Reliability versus validity

Page 5: Software Prediction Models Forecasting the costs of software development

Indicator 1: MMRE

Mean magnitude of relative error (MMRE) is an average where the MRE=|actual-prediction|/actual

Claimed advantages of MMRE– Compare across data sets*– Independent of units– Compare across differing prediction models*– Scale independence

*An hypothesis challenged by this paper

Page 6: Software Prediction Models Forecasting the costs of software development

Indicator 2: MER

Magnitude of the error relative to the estimate (MER) is defined asMER = |actual-prediction|/prediction

Page 7: Software Prediction Models Forecasting the costs of software development

Indicator 3: AR

The absolute residual (AR) is defined asAR = |actual-prediction|

Page 8: Software Prediction Models Forecasting the costs of software development

Other Measures

Standard deviation (SD) Relative standard deviation (RSD) Log standard deviation (LSD) Balanced relative error (BRE) Inverted balanced relative error (IBRE)

Page 9: Software Prediction Models Forecasting the costs of software development

Standard Deviation of Residuals, Denoted SD

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Page 10: Software Prediction Models Forecasting the costs of software development

Algebraic Simplification

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Page 11: Software Prediction Models Forecasting the costs of software development

Relative Standard Deviation (RSD)

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Page 12: Software Prediction Models Forecasting the costs of software development

Log Standard Deviation (LSD)

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Page 13: Software Prediction Models Forecasting the costs of software development

Balanced Relative Error (BRE)

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Page 14: Software Prediction Models Forecasting the costs of software development

Inverted Balanced Relative Error (IBRE)

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