Two-level 2-2-1: total and indirect e...
Message/Author
 Lucia posted on Wednesday, June 01, 2016 - 2:14 am
Hi!
I have a couple of questions about a two-level 2-2-1 mediation model, with random intercepts and cluster-robust standard errors.

The data are hierarchical (three-levels) and the main variables are the following:
*outcome (y) at level 1 = unordered categorical (nominal) with 3 categories

*mediator (m) at level 2 = binary

*predictor of interest (x1) at level 2 = categorical recoded into 2 dummies (x1_2 x1_3) and x_3 is the dummy of interest

1) Is it possible to estimate the indirect and total effects if the mediator (level 2) and the outcome (level 1) are measured at different levels and have different non-normal distributions (binomial and multinomial)?

2) If yes, how do we interpret the exponential of the indirect and total effects?
 Bengt O. Muthen posted on Wednesday, June 01, 2016 - 10:17 am
1) I think so. But how to express these effects correctly using counterfactuals may be a research topic - I don't recall having seen it expressed.

2) That's a later question, after the effects have been defined.

Counterfactual effects consider expectations which corresponds to probability Y=1 for a binary outcome Y. I recommend dichotomizing the outcome in two ways for two different analyses. An effect from a level 2 variable to a level 1 variable goes via the random intercept for the level 1 variable.
 Lucia posted on Tuesday, June 14, 2016 - 9:21 am

I have another question.

I dichotomized the output in two ways (y_1 and y_2) but the error indicates:
*** MODEL INDIRECT is not available for TYPE=TWOLEVEL with ALGORITHM=INTEGRATION.

My code is :
....
ANALYSIS: TYPE=COMPLEX TWOLEVEL;

MODEL:
%BETWEEN%
y_1 ON m ;
m ON x1_2 x1_3;

MODEL INDIRECT:
y2_1 IND x1_2;
y2_1 IND x1_3;

If the Numerical integration is required for the "COMPLEX TWOLEVEL" analysis, what's wrong with my code?

Thanks!
 Linda K. Muthen posted on Tuesday, June 14, 2016 - 9:22 am
 Robert Allen King posted on Monday, October 24, 2016 - 12:37 pm
Hello

I want to run a multiple mediated model and I am running into estimation issues. My guess is that I have done something wrong, but I wanted to make sure my code was right before I started diving deeper into causes.

Thank you for the help!
Robert

USEVARIABLES ARE
ID X
Y M1
M2
;
MISSING IS *;
CLUSTER = ID;
BETWEEN ARE M1 X;
ANALYSIS: TYPE = TWOLEVEL RANDOM;

MODEL:
%WITHIN% !INDIVIDUAL LEVEL
Y;
%BETWEEN% !GROUP LEVEL
M1 ON X (A1);
Y ON M1 (B1);
M2 ON X (A2);
Y ON M2 (B2);
Y ON X;

MODEL CONSTRAINT:
NEW (AB1
AB2);
AB1=A1*B1;
AB2=A2*B2;
OUTPUT: TECH1 TECH8 CINTERVAL;
 Bengt O. Muthen posted on Monday, October 24, 2016 - 3:07 pm
Should M2 also be put on the Between list?

Otherwise, I see no error.
 Robert Allen King posted on Tuesday, October 25, 2016 - 12:23 pm
Thank you for the help!
 Andrew Li posted on Tuesday, August 22, 2017 - 11:32 am
Dear Dr. Muthen,
I have a 2-2-1 model (x-m-y) model with the first path moderated by a level-2 moderator w. I also have a level-1 control C1 and a level-2 control C2. Would you please take a look at the code below and let me know if it is correct? Thank you.
missing = all(-999);
usevariables = a1 x m y w c1 c2 inter;
cluster = a1;
between = x m w c2 inter;
Within = c1;
define:
standardize x w;
inter = x * w;
analysis: type = twolevel random;
model:
%within%
y c1;
y on c1;
%between%
x m y w c2 inter;
m on
x (p1)
w
inter (p2);
y on
x
w
inter
m (b) c2;
model constraint:
new (ind1 ind2 wmo1 wmo2);
wmo1 = 1; !1 SD of the moderator W
wmo2 = -1; !-1 SD of the moderator W
ind1 = (p1+p2*wmo1)*b;
ind2 = (p1+p2*wmo2)*b;
output: tech1 tech8 cinterval;
 Bengt O. Muthen posted on Tuesday, August 22, 2017 - 6:06 pm
A quick look says that it seems alright - but don't rely on me; instead, check the literature.

And you can't have

m(b) c2;

You should say

m(b)

c2;