Re: News from the SPSS Community

Posted by Andy W on Oct 04, 2013; 5:41pm
URL: http://spssx-discussion.165.s1.nabble.com/News-from-the-SPSS-Community-tp5722365p5722383.html

FYI for those interested - Jon responded off list that the R package has more options for various link functions and estimating the variance as a separate parameter (which I did not even know was possible). So there are some obvious advantages to the R extension command over simply replicating the Smithson & Verkuilen CNLR routine.

Also as an FYI - Smithson and Verkuilen argue to use beta regression for not just proportion data, but Likert scale data with floor or ceiling effects. It seems if you have alot of ceiling effects though beta regression is probably not appropriate.

I've also seen suggestions for quantile regression and Tobit regression in such situations - see this related crossvalidated discussion http://stats.stackexchange.com/a/49450/1036. Jon also mentioned for these their is a Heckman regression approach as well (which I am not familiar with). I'm pretty sure Jon has already written R extension commands for all of these mentioned (so another thanks to Jon for putting this work in).