regression models for ordinal responses a review of methods

Once again the continuation ratio model does not

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Unformatted text preview: 2), 0.1 P 0.25. This suggests that the unconstrained partial proportional odds model, once again, fits the data better than the constrained partial proportional odds model. Graphical Methods of Assessing Model Fit and Model Constraints The assumptions of proportional odds and parallel slopes in the proportional odds and continuation ratio models, respectively, were examined by graphical methods. First, consider the fit of the proportional odds, unconstrained, and constrained partial proportional odds models to the laceration data. Relative risks estimated from each of these three models were contrasted to those based on the observed data (Figure 1). Clearly, the fit of a proportional odds model, constraining the relative risk to be 2.1 performs the least satisfactorily, while the fit of a constrained and unconstrained partial proportional odds models are almost identical, but an improvement over the proportional odds model. Note, however, that based on comparing the likelihood ratios between these two models the unconstrained partial proportional o...
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