regression models for ordinal responses a review of methods

In reality dichotomization can be somewhat arbitrary

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Unformatted text preview: seline category (i.e. women with no laceration). DISCUSSION Choice of an Ordinal Model The choice between the cumulative logit and continuation-ratio models merit further discussion. Armstrong and Sloan15 argue that when the cumulative logit model is valid implying that the cumulative logodds ratios are a constant, say β*, then the continuationratio model will begin at βj = β*, but will approach 0 as j increases. This argument has led to the cumulative logit model being proposed as an adjunct to the Cox’s proportional hazards model13 i.e. continuation-ratio model for survival data when hazard rates of groups are thought likely to converge with time (see McCullagh4 and McCullagh and Nelder14 for a more thorough discussion). The choice of a simple logistic model to an ordered response has its own disadvantages. Based on extensive simulations, Armstrong and Sloan15 conclude that the logistic model attains only between 50 and 75% efficiency, relative to the cumulative logit model for a fivelevel ordered response. Moreover, efficiency...
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