Mediation Model
Kwabenaaaddo
Joined: 02/01/2021
| Attachment | Size |
|---|---|
| Model | 142.1 KB |
Hello all,
I am trying to fit a mediation model where each of my main variables (BS, IND, WOB, DUA, BMEET and DIROWN) is mediated by another variable(BNKRISK). I have been following the model following Cheung (2021): Synthesizing Indirect Effects in Mediation Models with Meta-Analytic Methods: Supplementary Materials 2. I will proceed sequentially using to help you to follow the steps and where I encountered the error. This the model is
#Step 1##Mediation Model
model10 <- "PERF ~ c*BS + b*BNKRISK+f*IND+i*WOB+l*DUA+o*BMEET+r*DIROWN+BSIZE+LEV
BNKRISK ~ a*BS
BNKRISK ~ d*IND
BNKRISK ~ g*WOB
BNKRISK ~ j*DUA
BNKRISK ~ m*BMEET
BNKRISK ~ p* DIROWN
BS ~~ 1*BS
IND ~~ 1*IND
WOB ~~ 1*WOB
DUA ~~ 1*DUA
BMEET ~~ 1*BMEET
DIROWN ~~ 1*DIROWN
BSIZE ~~ 1*BSIZE
LEV ~~ 1*LEV
## Define indirect and direct effects
Ind_BS := a*b
Ind_IND := d*b
Ind_WOB := g*b
Ind_DUA := j*b
Ind_BMEET := m*b
Ind_DIROWN := p*b
Dir_BS := c
Dir_IND := f
Dir_WOB := i
Dir_DUA := l
Dir_BMEET := o
Dir_DIROWN := r"
When I plot the model using the syntax below, it is represented as I expect graphically (see the attached)
#Step 2##Display model
plot(model10)
However, when I attempt to fit the tssem, I face the following error, which is from the model I specified. The syntax to fit the model is this:
#Step 3# Convert the lavaan syntax to RAM specification used in metaSEM
RAM1 <- lavaan2RAM(model10, obs.variables= varnames)
RAM1
## Request the likelihood-based confidence interval
tssem.fit <- tssem2(stage1random, RAM=RAM1, intervals.type = "LB",
mx.algebras = list(ind_BS=mxAlgebra(a*b, name="ind_BS"),ind_IND=mxAlgebra(d*b, name="ind_IND"),ind_WOB=mxAlgebra(g*b, name="ind_WOB"),ind_DUA=mxAlgebra(j*b, name="ind_DUA"),ind_BMEET=mxAlgebra(m*b, name="ind_BMEET"),ind_DIROWN=mxAlgebra(p*b, name="ind_DIROWN"),
Dir_BS=mxAlgebra(c, name="Dir_BS"),Dir_IND=mxAlgebra(f, name="Dir_IND"),Dir_WOB=mxAlgebra(i, name="Dir_WOB"),Dir_DUA=mxAlgebra(l, name="Dir_DUA"),Dir_BMEET=mxAlgebra(o, name="Dir_BMEET"),Dir_DIROWN=mxAlgebra(r, name="Dir_DIROWN")))
The error report as :
Error in running the mxModel:
Warning messages:
1: In .solve(x = object$mx.fit@output$calculatedHessian, parameters = my.name) :
Error in solving the Hessian matrix. Generalized inverse is used. The standard errors may not be trustworthy.
2: Unknown reference 'd' detected in the entity 'ind_IND' in model 'TSSEM2 Correlation' .
Can anyone help me with where I specified the model wrongly? Thanks in advance
Regards.
Please provide the data and R
Please provide the data and R code for reproducibility.
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In reply to Please provide the data and R by Mike Cheung
Dear Prof Cheung,
Dear Prof Cheung,
Many thanks for your response. I have attached the data and codes as requested.
Could you let me know if it is still good to run my 2nd stage (model) with the stage1 or stage1_rerun estimates.
Kindest Regards.
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As there are only a few data
As there are only a few data points in some of these cells, there are not enough data to compute the average correlation matrix.
> pattern.na(cordat, show.na = FALSE)
BS IND WOB DUA BMEET DIROWN BNKRISK BSIZE LEV PERF
BS 142 108 29 36 17 14 78 96 89 111
IND 108 146 30 34 20 14 95 90 77 113
WOB 29 30 36 9 7 2 23 25 22 29
DUA 36 34 9 54 5 3 34 35 32 36
BMEET 17 20 7 5 25 1 14 19 10 21
DIROWN 14 14 2 3 1 19 7 8 11 13
BNKRISK 78 95 23 34 14 7 127 81 72 97
BSIZE 96 90 25 35 19 8 81 143 88 114
LEV 89 77 22 32 10 11 72 88 127 99
PERF 111 113 29 36 21 13 97 114 99 169
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