[R] R vs SPSS contrasts

[Gabor Grothendieck]

Don't know but perhaps you could just use each of:
contr.helmert, contr.poly, contr.sum, contr.treatment, contr.SAS
in turn on the R side until you get one that matches.  Once you
find out adding a contr.SPSS to R might be nice.

On Sat, Oct 11, 2008 at 3:31 PM, Ted Harding
<Ted.Harding at manchester.ac.uk> wrote:
> Hi Folks,
>
> I'm comparing some output from R with output from SPSS.
> The coefficients of the independent variables (which are
> all factors, each at 2 levels) are identical.
>
> However, R's Intercept (using default contr.treatment)
> differs from SPSS's 'constant'. It seems that the contrasts
> were set in SPSS using
>
>  /CONTRAST (varname)=Simple(1)
>
> I can get R's Intercept to match SPSS's 'constant' if I use
> contr.sum in R.
>
> Can someone please confirm that that is a correct match for
> the SPSS "Simple(1)", with identical effect?
>
> And is there a convenient on-line reference where I can look
> up what SPSS's "/CONTRAST" statements exactly mean?
> I've done a lot of googling, withbout coming up with anything
> satisfactory.
>
> With thanks,
> Ted.
>
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> E-Mail: (Ted Harding) <Ted.Harding at manchester.ac.uk>
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> Date: 11-Oct-08                                       Time: 20:31:53
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