The OUTMODEL= data set contains the model specification, the computed parameter estimates, and the standard error estimates. This data set is intended to be reused as an INMODEL= data set in a subsequent analysis by PROC IRT.
The OUTMODEL= data set contains the following variables:
BY variables, if any
_GPNUM_ variable for group numbers, if used
_TYPE_, a character variable that takes various values that indicate the type of model specification
_SUBTYP_, a character variable that takes various values that indicate the type of model parameters
_NAME_, a character variable that indicates the model type, parameter name, or variable name
_NUM_, a numeric variable that takes various values that indicate model specifications such as the number of items, number of factors, number of groups, and number of levels for each item
_VAR1_, a character variable that is the name or number of the first variable in the specification
_VAR2_, a character variable that is the name or number of the second variable in the specification
_ESTIM_, a numeric variable that is the final estimate of the parameter
_STDERR_, a numeric variable that is the standard error estimate of the parameter
Each observation (record) of the OUTMODEL= data set contains a piece of information about the model specification. Depending on the type of specification that the value of the _TYPE_ variable indicates, the meanings of the _SUBTYP_, _NAME_, _NUM_ _VAR1_, and _VAR2_ variables differ. Table 3 summarizes the meanings of these variables for each value of the _TYPE_ variable.
Table 3: Meaning of Variables in the OUTMODEL=Data Set
_TYPE_ |
Description | _SUBTYP_ |
_NAME_ |
_NUM_ |
_VAR1_ |
_VAR2_ |
|---|---|---|---|---|---|---|
| MODEL | Model Info | NGROUP | Number of groups | |||
| MODEL | Model Info | NITEM | Number of items | |||
| MODEL | Model Info | NFACTOR | Number of factors | |||
| MODEL | Model Info | LINK | Link function | |||
| MODEL | Model Info | RORDER | RORDER option | |||
| MODEL | Model Info | DESC | DESC option | |||
| VAR | Variable | Name | Number of levels | Response function | ||
| VAR | Variable | LEVINFO | Name | Level | Level value | |
| FACTOR | Factor | Name | ||||
| GPVAR | Group | Group var name | ||||
| PRIOR | Prior Info | CEILING | Variable | |||
| PRIOR | Prior Info | GUESSING | Variable | |||
| PRIOR | Prior Info | SLOPE | Variable | |||
| PARM | Parameter | CEILING | Name | Number | Variable | |
| PARM | Parameter | GUESSING | Name | Number | Variable | |
| PARM | Parameter | INTERCEPT | Name | Number | Variable | Category |
| PARM | Parameter | SLOPE | Name | Number | Variable | Factor |
| PARM | Parameter | COV | Name | Number | 1st variable | 2nd variable |
| PARM | Parameter | MEAN | Name | Number | Variable |
For computational convenience, the intercept parameters rather than the threshold (or difficulty) parameters are saved in the OUTMODEL= data set. For multidimensional exploratory analysis, the OUTMODEL= data set includes the unrotated factor loading matrix. In the OUTMODEL= data set, fixed parameters do not have names but only parameter numbers. For free parameters, the OUTMODEL= data set includes the parameter name and the parameter number. When this data set is used for the INMODEL= option, PROC IRT sets an equality constraint for parameters that have the same name.