## Model Type III Sum of Squares [General Sta­tis­tics]

Thanks so much ElMaestro.

» Type III SS for a factor A is essentially the SS for A given B and C in the model. I guess you might refer to that as SS(A|B∩C),

OK, so that implies that Type III for factor B and C becomes SS(B|A∩C) and SS(C|A∩B) respectively?

How about Type I SS for factors A, B and C (in that order)? Would it be SS(A), SS(B|A) and SS(C|A∩B) respectively?

» but check it with someone who understands statistics. I don't.

I think your knowledge of statistics is fine enough for me. The statisticians around me are not in the medical field thus they end up confusing me most times.

» Correct, but note the meaning of balance may differ for other designs; traditionally in BE balance is when you have an equal number of evaluable completers in RT and TR and when the analysis only involves those evaluable completers.

OK that's true. This could possibly be part of the reason why Type I and type III SS are not the same even in a balanced BE design.

» Orthogonality is a quite abstract term and entire books are written about it. In this context it means you can partition the variability onto the factors of the design. FDA used the term in a presentation some years ago about in vivo and in vitro factors that affect bioequivalence testing for OIPs and suddenly everybody was talking about orthogonality in a grandiose hodgepodge of confusion.
» The community has not recovered yet. If you mention something that could hypothetically affect the outcome of a BE trial or treatment success (like inhaler training, or lactose grade, or an image of mickey mouse printed on the side of the inhaler to make it appealing to children) people will unhesitatingly ask if that's an orthogonal factor.

Well, I guess I shouldnt wake up the orthogonal monster

Scopy