It really is just a matter of justifying and explaining your chosen statistical model. If you believe that two groups have the same regression slope for a parameter (but possibly different offsets/intercepts), then you would use a "DOSS" model -- this is akin to a model in SPSS/SAS in which you model a main effect of group and a single (main) effect of the regressor that applies to all subjects (e.g., Y = group age). If you believe that the two groups might possibly have a different slope, then you would use a "DODS" model (also known as a heterogeneous slopes model) -- this is equivalent to a model in SPSS/SAS in which you model a main effect of group (different offsets/intercepts) and separate (heterogeneous) slopes for the two groups i.e,. you model a possible interaction between group and slope; Y = group age group*age).
cheers, -MH
On Tue, 2011-02-01 at 20:49 +0100, Christian Scheel wrote:
Dear all,
does anyone know one or two good method papers to cite when describing the difference of DOSS and DODS? I have already screened Pubmed and Co. but did not really find anything convincing.
Any help greatly appreciated!
Best wishes, Christian Scheel
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