SPSS® 12.0 Command Syntax Reference

848 MANOVA: Univariate
• To obtain F tests for individual degrees of freedom for the specified contrast, enter the factor
name followed by a number in parentheses on the DESIGN subcommand. The number
refers to a partition of the factor’s degrees of freedom. If you do not use the PARTITION
subcommand, each degree of freedom is a distinct partition.
The following contrast types are available:
DEVIATION Deviations from the grand mean. This is the default for between-subjects
factors. Each level of the factor except one is compared to the grand mean.
One category (by default the last) must be omitted so that the effects will be
independent of one another. To omit a category other than the last, specify
the number of the omitted category (which is not necessarily the same as its
value) in parentheses after the keyword DEVIATION. For example,
MANOVA A BY B(2,4)
/CONTRAST(B)=DEVIATION(1).
The specified contrast omits the first category, in which B has the value 2.
Deviation contrasts are not orthogonal.
POLYNOMIAL Polynomial contrasts. This is the default for within-subjects factors. The
first degree of freedom contains the linear effect across the levels of the
factor, the second contains the quadratic effect, and so on. In a balanced
design, polynomial contrasts are orthogonal. By default, the levels are
assumed to be equally spaced; you can specify unequal spacing by entering
a metric consisting of one integer for each level of the factor in parentheses
after the keyword POLYNOMIAL. For example,
MANOVA RESPONSE BY STIMULUS (4,6)
/CONTRAST(STIMULUS) = POLYNOMIAL(1,2,4).
The specified contrast indicates that the three levels of STIMULUS are actually
in the proportion 1:2:4. The default metric is always (1,2,...,k), where k
levels are involved. Only the relative differences between the terms of the
metric matter (1,2,4) is the same metric as (2,3,5) or (20,30,50) because, in
each instance, the difference between the second and third numbers is twice
the difference between the first and second.
DIFFERENCE Difference or reverse Helmert contrasts. Each level of the factor except the
first is compared to the mean of the previous levels. In a balanced design,
difference contrasts are orthogonal.
HELMERT Helmert contrasts. Each level of the factor except the last is compared to
the mean of subsequent levels. In a balanced design, Helmert contrasts are
orthogonal.
SIMPLE Each level of the factor except the last is compared to the last level. To use
a category other than the last as the omitted reference category, specify its
number (which is not necessarily the same as its value) in parentheses
following the keyword SIMPLE. For example,
MANOVA A BY B(2,4)
/CONTRAST(B)=SIMPLE(1).