Mplus Users Guide v6.. - Muthén & Muthén

CHAPTER 14in the other two groups. The model for g3 is identical to that of theoverall model because there is no group-specific model statement for g3.EQUALITIES IN MULTIPLE GROUP ANALYSISA number or list of numbers in parentheses following a parameter or listof parameters is used to indicate equality constraints. Constrainingparameters to be equal in a single group analysis is discussed in Chapter17. In a single group analysis, parameters are constrained to be equal byplacing the same number or list of numbers in parentheses following theparameters that are to be held equal. For example,y1 ON x1 (1) ;y2 ON x2 (1) ;y3 ON x3 (2) ;y4 ON x4 (2) ;y5 ON x5 (2) ;constrains the regression coefficients of the first two equations to beequal and the regression coefficients of the last three equations to beequal.In multiple group analysis, the interpretation of equality constraintsdepends on whether they are part of the overall MODEL command or agroup-specific MODEL command. Equality constraints specified in theoverall MODEL command apply to all groups. Equality constraintsspecified in a group-specific MODEL command apply to only thatgroup.Following is an example of how to specify across group equalityconstraints in the overall MODEL command:MODEL:f1 BY y1-y5;y1 (1)y2 (2)y3 (3)y4 (4)y5 (5);By placing a different number in parentheses after each residualvariance, each residual variance is held equal across all groups but not426