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Modeling and Multivariate Methods - SAS

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Chapter 25 Comparing Model Performance 633<br />

The Model Comparison Report<br />

The Model Comparison Report<br />

Figure 25.6 shows an example of the initial Model Comparison report for a continuous response.<br />

Figure 25.6 Initial Model Comparison Report<br />

The Predictors report shows all responses <strong>and</strong> all models being compared for each response. The fitting<br />

platform that created the predictor column is also listed.<br />

The Measures of Fit report shows measures of fit for each model. The columns are different for continuous<br />

<strong>and</strong> categorical responses.<br />

Measures of Fit for Continuous Responses<br />

RSquare<br />

The r-squared statistic.<br />

RASE The root average squared error, the same value as RMSE except that RMSE adjusts for degrees of<br />

freedom.<br />

AAE<br />

Freq<br />

The average absolute error.<br />

The column that contains frequency counts for each row.<br />

Measures of Fit for Categorical Responses<br />

Entropy RSquare One minus the ratio of the -log-likelihoods from the fitted model <strong>and</strong> the constant<br />

probability model. It ranges from 0 to 1.<br />

Generalized RSquare A generalization of the Rsquare measure that simplifies to the regular Rsquare for<br />

continuous responses. Similar to the Entropy RSquare, but instead of using the log-likelihood, the<br />

Generalized RSquare uses the 2/n root of the likelihood. The maximum value is 1 for a perfect model.<br />

A value of 0 indicates that the model is no better than a constant model.<br />

Mean -Log p<br />

occurred.<br />

The average of -log(p), where p is the fitted probability associated with the event that<br />

RMSE The root mean square error, adjusted for degrees of freedom. For categorical responses, the<br />

differences are between 1 <strong>and</strong> p (the fitted probability for the response level that actually occurred).

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