[R] R vs SPSS contrasts

[(Ted Harding)]

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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