Mplus Users Guide v6.. - Muthén & Muthén

TITLE, DATA, VARIABLE, And DEFINE CommandsTHE DATA IMPUTATION COMMANDThe DATA IMPUTATION command is used when a data set containsmissing values to create a set of imputed data sets using multipleimputation methodology. Imputation refers to the estimation of missingvalues in a data set to create a data set without missing values. Multipleimputation refers to the creation of several data sets where missingvalues have been imputed. Multiple imputation is carried out usingBayesian estimation. The multiple imputations are random draws fromthe posterior distribution of the missing values (Rubin, 1987; Schafer,1997). For an overview, see Enders (2010). The multiple imputationdata sets can be used for subsequent model estimation using maximumlikelihood or weighted least squares estimation of each data set wherethe parameter estimates are averaged over the data sets and the standarderrors are computed using the Rubin formula (Rubin, 1987). A chisquaretest of overall model fit is provided (Asparouhov & Muthén,2008c; Enders, 2010)The imputed data sets can be saved for subsequent analysis or analysiscan be carried out at the time the imputed data sets are created. If thedata sets are saved for subsequent analysis, TYPE=BASIC should bespecified in the ANALYSIS command. In this case, the data areimputed using an unrestricted H1 model. The SAVE option is describedbelow. A subsequent analysis is carried out using the IMPUTATIONsetting of the TYPE option of the DATA command.If the data sets are created when an estimator other than BAYES is usedfor model estimation, the data are imputed using an unrestricted H1model. If the data sets are created when the BAYES estimator is usedfor model estimation, the data sets are imputed using the H0 modelspecified in the MODEL command.IMPUTEThe IMPUTE option is used to specify the analysis variables for whichmissing values will be imputed. Data can be imputed for all or a subsetof the analysis variables. These variables can be continuous orcategorical. If they are categorical a letter c in parentheses must beincluded after the variable name. If a variable is on theCATEGORICAL list in the VARIABLE command, it must have a c in461