One commonly used model to analyze ordinal response data is the proportional odds (PO) model. However, if research interest is focused on a particular category and if an individual must pass through lower categories before achieving a higher level, the continuation ratio (CR) model is a more appropriate choice than the PO model. In addition, statistical software, such as Stata and SAS, may use different techniques to estimate the parameters. The CR model is used to illustrate the analysis of ordinal data in education using Stata and SAS and compares the results of fitting the CR model between these two packages.
Liu, Xing; O'Connell, Ann A.; and Koirala, Hari
"Ordinal Regression Analysis: Predicting Mathematics Proficiency Using the Continuation Ratio Model,"
Journal of Modern Applied Statistical Methods:
2, Article 11.
Available at: http://digitalcommons.wayne.edu/jmasm/vol10/iss2/11