user manual

65
Complex Samples Ordinal Regression
Figure 11-1
Ordinal Regression dialog box
E Select a dependent variable.
Optionally, you can:
 Select variables for factors and covariates, as appropriate for your data.
 Specify a variable to define a subpopulation. The analysis is performed only for the selected
category of the subpopulation variable, although variances are still properly estimated based
on the entire dataset.
 Select a link function.
Link function. The link function is a transformation of the cumulative probabilities that allows
estimation of the model. Five link functions are available, summarized in t he following table.
Function
Form
Typical application
Logit log( ξ /(1−ξ) ) Evenly distributed catego ries
Complementary log-log log(−log(1−ξ)) Higher c ategories more probable
Negative log-log −log(−log(ξ)) Lower cate gories more probable
Probit Φ
−1
(ξ) Latent va r iable is normally
distributed
Cauchit (inverse Cauchy) tan(π(ξ−0.5)) Latent variable has many extrem e
values