Mixed-effects logistic regression models are described for analysis of longitudinal ordinal outcomes, where observations are observed clustered within subjects. Random effects are included in the model to account for the correlation of the clustered observations. Typically, the error variance and the variance of the random effects are considered to be homogeneous. These variance terms character...

For most of the time, biomedical researchers have been dealing with ordinal outcome variable in multilevel models where patients are nested in doctors. We can justifiably apply multilevel cumulative logit model, where the outcome variable represents the mild, severe, and extremely severe intensity of diseases like malaria and typhoid in the form of ordered categories. Based on our simulation co...

When a binary or ordinal regression model incorrectly assumes that error variances are the same for all cases, the standard errors are wrong and (unlike OLS regression) the parameter estimates are biased. Heterogeneous choice (also known as location-scale or heteroskedastic ordered) models explicitly specify the determinants of heteroskedasticity in an attempt to correct for it. Such models are...

Purpose To evaluate the inter-rater reliability and predictive validity of the Frenchay Activities Index (FAI) in patients after stroke. Methods One hundred sixty-one patients were selected for consecutive application of the FAI and National Institutes of Health Stroke Scale (NIHSS). Spearman's test was used for correlation between different scales. The FAI and NIHSS association was evaluated...

For categorical data, the relationship between visual displays of the data and models is not very well explored, even though for categorical data and loglinear models strong relationships do exist. Starting from assessing odds ratios visually, interaction effects of variables can be examined using mosaic plots. Cumulative link models provide a way to describe trends between ordinal variables. I...

OBJECTIVE To investigate factors associated with subsyndromal depression (SSD) in very old persons, and to develop a model for prediction of SSD among very old persons. METHODS A cross-sectional, population-based study was undertaken on 85-year-old persons in Sweden. Data were collected from a postal questionnaire, assessments in the participants' homes and at reception visits. Depressiveness...

The stereotype logistic (SL) model is an alternative to the proportional odds (PO) model for ordinal response variables when the proportional odds assumption is violated. This model seems to be underutilized. One major reason is the constraint of current statistical software packages. Statistical Package for the Social Sciences (SPSS) cannot perform the SL regression analysis, and SAS does not ...

Epileptic seizures are associated with high behavioral stereotypy of the patients. In the EEG of epilepsy patients characteristic signal patterns can be found during and between seizures. Here we use ordinal patterns to analyze EEGs of epilepsy patients and quantify the degree of signal determinism. Besides relative signal redundancy and the fraction of forbidden patterns we introduce the fract...