Moderated mediation command error PreviousNext
Mplus Discussion > Structural Equation Modeling >
Message/Author
 Yina posted on Sunday, September 01, 2013 - 12:28 pm
I used Mplus to test a moderated mediation model, in which only first stage moderation is hypothesized. X is predictor, Y is outcome variable, M is mediator and W is moderator. I labled coefficients (B1-B4) when the model is specified. However, I get error information that " Unknown variable(s) in an ON statement: (B1)".I guess I might encounter similar warnings with B2-B4 too. Here is my command:

TITLE: MODMED MODEL;
DEFINE:
XW = (X - 2) * (W - 3);
DATA: FILE IS MODMED.DAT;
VARIABLE: NAMES ARE X M W Y;
USEVARIABLES ARE X M W Y XW;
CENTERING IS GRANDMEAN (X M W);
ANALYSIS: BOOTSTRAP = 2000;
MODEL:
M ON X(B1) XW(B2);
Y ON M X(B3) XW(B4);
MODEL CONSTRAINT:
NEW (SLOPE_H SLOPE_L SLOPE_D);!h/l refers to when moderator is high or low, d refers to difference
SLOPE_H = B1 + B2 * 0.5;
SLOPE_L = B1 + B2 * (-0.5);
SLOPE_D = SLOPE_H - SLOPE_L;
NEW (DIR_H DIR_L DIR_D);!DIR refers to direct effect
DIR_H = B3 + B4 * 0.5;
DIR_L = B3 + B4 * (-0.5);
DIR_D = DIR_H - DIR_L;
OUTPUT:
SAMPSTAT;
CINTERVAL (BCBOOTSTRAP);

What am I doing wrong? Thank you!
 Linda K. Muthen posted on Sunday, September 01, 2013 - 12:55 pm
Please send your full output and license number to support@statmodel.com.
Back to top
Add Your Message Here
Post:
Username: Posting Information:
This is a private posting area. Only registered users and moderators may post messages here.
Password:
Options: Enable HTML code in message
Automatically activate URLs in message
Action: