Douglas Bates kommentiert MIXED in SPSS (Oder: lme4 vs MIXED)
Douglas Bates ist Autor des R packages lme4 mit dem sich gemischte Modelle (lineare und verallgemeinerte lineare Mehrebenmodelle) schätzen lassen. In einem thread auf der r-help-list hat er sich vor kurzem zur Dokumentation der MIXED-Funktion in SPSS ausgelassen. So fing alles an:
“My particular interest is in the methods for the linear mixed models implemented in MIXED in SPSS (and also PROC MIXED in SAS). A person who was quite enthusiastic about the MIXED procedure in SPSS sent me a PDF file about MIXED that I suppose could be considered a description of the algorithms as long as you didn’t read it too closely.”
Seine Bewertung fällt eindeutig aus:
“Even more alarming, parts of it are flat-out wrong. Even the mixed-model equations as given in this document are wrong, as one would quickly find out if one tried to implement them. The organization is disjointed and generally the language and grammar indicate that it has not been copy edited carefully. I would not give it a good grade if it were submitted as a project report in my statistical computing course.”
Er schränkt seine harsche Kritik etwas ein, wenn er anmerkt, dass er die Quelle des Dokuments nicht finden konnte.
“I have been unable to trace the source of this document. It is definitely a discussion of the computational algorithms in MIXED but I haven’t been able to track its original source. In a way I hope it was a preliminary draft or something like that. If SPSS released this version as an official publication it is a sign that they have fallen on hard times.”
