Mplus Users Guide v6.. - Muthén & Muthén

TITLE, DATA, VARIABLE, And DEFINE CommandsTHIN = 200;THE DATA TRANSFORMATION COMMANDSThere are six DATA transformation commands. They are used torearrange data from a wide to long format, to rearrange data from a longto wide format, to create a binary and a continuous variable from asemicontinuous variable, to create a set of binary variables that areindicators of missing data for another set of variables, to create variablesfor discrete-time survival modeling where a binary variable representsthe occurrence of a single non-repeatable event, and to rearrangelongitudinal data from a format where time points representmeasurement occasions to a format where time points represent age oranother time-related variable.THE DATA WIDETOLONG COMMANDIn growth modeling an outcome measured at four time points can berepresented in a data set in two ways. In the wide format, the outcome isrepresented as four variables on a single record. In the long format, theoutcome is represented as a single variable using four records, one foreach time point. The DATA WIDETOLONG command is used torearrange data from a multivariate wide format to a univariate longformat.When the data are rearranged, the set of outcomes is given a newvariable name and ID and repetition variables are created. These newvariable names must be placed on the USEVARIABLES statement ofthe VARIABLE command if they are used in the analysis. They must beplaced after any original variables. If the ID variable is used as a clustervariable, this must be specified using the CLUSTER option of theVARIABLE command.The creation of the new variables in the DATA WIDETOLONGcommand occurs after any transformations in the DEFINE command andany of the other DATA transformation commands. If listwise deletion isused, it occurs after the data have been rearranged. Following is adescription of the options used in the DATA WIDETOLONG command.465