Diagnostics for Stratified Clinical Trials in Proportional Odds Models

Abstract

For stratified clinical trials with an ordinal response, this article considers two diagnostics strategies for evaluating the heterogeneity of the ordinal odds ratios across multi-centers in proportional odds models. The first strategy assumes multi-centers as a sample from a population and then uses a proportional odds model allowing random effects to model the heterogeneity among the ordinal log odds ratios. It gives an overall view of the heterogeneity across multi-centers. The second strategy applies the influence measure to the Mantel–Haenszel type estimators of the ordinal odds ratios. It shows the detail of heterogeneity in each of the multi-centers. At the end, this article uses a multi-center clinical trials example to illustrate both strategies.

Keywords:

• Clinical trials
• Cumulative odds ratio
• Diagnostics
• Influence measure
• Mantel–Haenszel estimator
• Ordinal response
• Proportional odds model
• Random effects
• Strata deletion

Mathematics Subject Classification:

• Primary 62J20
• Secondary 62P10

Acknowledgment

We would like to thank Megan Clark and the referee for their helpful comments.

Notes

Note: Response is scaled from better (1) to worse (4).