GENMOD, GEE,CLASS statments and the order of the variables therein

Discussion in 'SAS (Statistical Analysis Software)' started by Dale McLerran, Apr 16, 2004.

  1. Michael,

    You are absolutely correct. Thanks for pointing out my error.
    For the difference a1-a2 @ b1, I should have the A main effect
    contrast coefficients 1 -1. Likewise for the contrasts a1-a2 @ b2
    and a1-a2 @ b3. For the contrast b1-b2 @ a1 I should have the
    B main effect contrast coefficients 1 -1 0. I'll let folks
    determine what other B main effect contrast coefficients should
    be employed for other estimate statements of the form bi-bj @ ak.

    I was trying to focus on just the part of the contrast matrix
    matrix involving the crossed effects to show how inattention to
    the order of the variables in the CLASS statement would cause
    problems there. I should have put some ellipses in my estimate
    statements as place holders for the main effect differences
    which need to be included in the estimate statements to convey
    that there is another part of the effect contrast which needs
    to be included.


    Dale McLerran
    Fred Hutchinson Cancer Research Center
    Ph: (206) 667-2926
    Fax: (206) 667-5977

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    Dale McLerran, Apr 16, 2004
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