Correlations

This table displays two statistics, Pearson's R and Kendall's tau, which provide measures of the correlation between the observed and estimated preferences.

The table also displays Kendall's tau for just the holdout profiles. Remember that the holdout profiles (four in the present example) were rated by the subjects but not used by the Conjoint procedure for estimating utilities. Instead, the Conjoint procedure computes correlations between the observed and predicted rank orders for these profiles as a check on the validity of the utilities.

In many conjoint analyses, the number of parameters is close to the number of profiles rated, which will artificially inflate the correlation between observed and estimated scores. In these cases, the correlations for the holdout profiles may give a better indication of the fit of the model. Keep in mind, however, that holdouts will always produce lower correlation coefficients.

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