REPEATED Subcommand (MIXED command)
The REPEATED
subcommand specifies the residual covariance matrix in the mixed-effects
model. If no REPEATED
subcommand
is specified, the residual covariance matrix assumes the form of a
scaled identity matrix with the scale being the usual residual variance.
- Specify a list of variable names (of any type) connected
by asterisks (repeated measure) following the
REPEATED
subcommand. - Distinct combinations of values of the variables are used simply to identify the repeated observations. Order of the values will determine the order of occurrence of the repeated observations. Therefore, the lowest values of the variables associate with the first repeated observation, and the highest values associate with the last repeated observation.
- The
VC
covariance structure is obsolete in theREPEATED
subcommand. If it is specified, it will be replaced with theDIAG
covariance structure. An annotation will be made in the output to indicate this change. - The default covariance type for repeated effects is
DIAG
. - The following keywords, which are specific for the
REPEATED
subcommand, can be entered after the effects. Use the vertical bar (|) to precede the options.- SUBJECT(varname*varname*…)
- Identify the subjects. Complete independence is assumed across subjects, thus producing a block-diagonal structure in the residual covariance matrix with identical blocks. The number of subjects is equal to the number of distinct combinations of values of the variables. A case will not be used if it contains a missing value on any of the subject variables.
- KRONECKER(varname*varname*…)
- The Kronecker product of two matrices can handle doubly repeated-measure data in which there are
two repeated effects; one of them indicating the multivariate observation of target, and the other
the time or the order of the data measured. The
KRONECKER
keyword should be used only whenCOVTYPE
is defined asUN_AR1
,UN_CS
, orUN_UN
. - COVTYPE(type)
- Covariance structure. Specify the covariance structure of the identical blocks for the residual
covariance matrix (see Covariance Structure List (MIXED command)).
The default structure for repeated effects is
DIAG
. - SPCOORDS(varname...)
- Specifies the variables that define the spatial covariance coordinates. One or more numeric
variables must be specified.
SPCOORDS
is required whenSP_POWER
,SP_EXPONENTIAL
,SP_GAUSSIAN
,SP_LINEAR
,SP_LINEARLOG
, orSP_SPHERICAL
is specified for theCOVTYPE
keyword. It is ignored otherwise.
- The
SUBJECT
keyword must be specified to identify the subjects in a repeated measurement analysis. The analysis will not be performed if this keyword is omitted. - The list of subject variables must contain all of
the subject variables specified in all
RANDOM
subcommands. - Any variable used in the repeated measure list must not be used in the repeated subject specification.
Example
MIXED SCORE BY CLASS
/RANDOM = CLASS | SUBJECT(SCHOOL)
/REPEATED = FLOOR | SUBJECT(SCHOOL*STUDENT).
However, the syntax in each of the following examples is invalid:
MIXED SCORE BY CLASS
/RANDOM = CLASS | SUBJECT(SCHOOL)
/REPEATED = FLOOR | SUBJECT(STUDENT).
MIXED SCORE BY CLASS
/RANDOM = CLASS | SUBJECT(SCHOOL*STUDENT)
/REPEATED = FLOOR | SUBJECT(STUDENT).
MIXED SCORE BY CLASS
/RANDOM = CLASS | SUBJECT(SCHOOL)
/REPEATED = STUDENT | SUBJECT(STUDENT*SCHOOL).
- In the first two examples, the
RANDOM
subject list contains a variable not on theREPEATED
subject list. - In the third example, the
REPEATED
subject list contains a variable on theREPEATED
variable list.