The response design forms the M matrix. The columns of an M matrix define a set of transformation variables for the multivariate analysis. The Choose Response button contains the following options for the M matrix:
Repeated Measures
Constructs and runs both Sum and Contrast responses.
Sum
Sum of the responses that gives a single value.
Identity
Uses each separate response, the identity matrix.
Contrast
Compares each response and the first response.
Polynomial
Constructs a matrix of orthogonal polynomials.
Helmert
Compares each response with the combined responses listed below it.
Profile
Compares each response with the following response.
Mean
Compares each response with the mean of the others.
Compound
Creates and runs several response functions that are appropriate if the responses are compounded from two effects.
Custom
Uses any custom M matrix that you enter.
The most typical response designs are Repeated Measures and Identity for multivariate regression. There is little difference in the tests given by the Contrast, Helmert, Profile, and Mean options, since they span the same space. However, the tests and details in the Least Squares means and Parameter Estimates tables for them show correspondingly different highlights.
The Repeated Measures and the Compound options display dialogs to specify response effect names. They then fit several response functions without waiting for further user input. Otherwise, selections expand the control panel and give you more opportunities to refine the specification.