Message/Author 

li weidong posted on Thursday, September 15, 2011  2:45 am



Dear Mr.Muthen, I use Mplus 6.1DEMO to test the significance of multiple mediation. I set the bootstrap number as 1000,2000,5000. However,the Mplus outputs always report the same results as in doing normal analysis which not use bootstrap method except the S.E.is different. Could you tell me what"s wrong with my analysis? Thank you very much! Best Regards! li weidong 2011915 


We only bootstrap the standard errors. So only the standard errors will be different. 

li weidong posted on Friday, September 16, 2011  11:57 pm



Thank you,Linda. It is very nice of you! Can I report the parameter bootstrap results with other SEM software(i.e. AMOS)and corresponding standard errors with Mplus? 


I don't think the Mplus bootstrapped standard error would be appropriate for the bootstrapped parameter estimate. 

li weidong posted on Monday, October 17, 2011  12:48 am



Hi!Linda, I have a question which puzzled me so far. As in Bollen & Stine(1990),the bootstrapped standard errors were generated with the average estimation of the bootstrapped unstandardized or standardized indirect effects.How can Mplus only bootstrap the standard errors without bootstrap the unstandardized or standardized indirect effects? I do want to know how Mplus cannot report the bootstrapped unstandardized indirect effects or the standard errors of standardized indirect effects? if I report the results from Mplus as above,in which degree I can trust the results? Many thanks to you and your team for developing this powerful analytic tool! best regards! liweidong 20111017 


There are several different options in Mplus about how the bootstrap SE are computed. The basic version is this: for each bootstrap sample we estimate the model then we compute the standard deviation of these estimates. This approach is used for the model estimates, the standardized estimates and the indirect effect estimates. 


A nice introduction to the bootstrap methodology can be found here http://www.amazon.com/IntroductionBootstrapMonographsStatisticsProbability/dp/0412042312 The basic version of bootstrap does not affect the point estimates, only the standard errors. 

li weidong posted on Monday, October 17, 2011  11:48 pm



Thank you very much! 

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