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bootstrapping indirect effects

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pascofearon's picture
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Joined: 05/07/2013 - 10:57
bootstrapping indirect effects

Hi Mike,
Hope you're well. I was just wondering whether there's a simple way to bootstrap the indirect effect in metasem (tssem2 or osmasem).

Thanks,

Best wishes,

Pasco

pascofearon's picture
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Joined: 05/07/2013 - 10:57
bootstrapping indirect effects

Hi Mike,
I think I figured it out, but would appreciate a thumbs up if you have time:

ind <- mxAlgebra(a*b, name="ind")

fit1 <- osmasem(model.name="test", Mmatrix=M1, Tmatrix=T0, data=dat, intervals.type=c("LB"), mxModel.Args = list(ind, mxCI(c("ind"))), suppressWarnings=FALSE)
summary(fit1)

boot1<-mxBootstrap(fit1$mx.fit)
summary(boot1, summary(boot1, boot.quantile=c(.025,.975)))
mxBootstrapEval(ind, boot1, bq=c(.025,.975))

Mike Cheung's picture
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Joined: 10/08/2009 - 22:37
Hi Pasco,

Hi Pasco,

Your code seems correct.

There are at least two issues in the bootstrap CI in MASEM: (1) the number of studies tends to be small; (2) there may be many missing correlations in the studies. But I would prefer the LBCI unless there is evidence to show the other way.

Best,
Mike

pascofearon's picture
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Joined: 05/07/2013 - 10:57
Thanks Mike! We have a

Thanks Mike! We have a reviewer 3 with strong views about this.... but your take is extremely helpful!