Moderation Model - negative estimates
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AgeMod.txt | 9.78 KB |
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Hi,
I adapted script from the Boulder workshop to test a univariate twin model with age moderating the variance components of observational data (one single global score per twin member). When I run the model, I get a non-zero status code 6, but I can get the model to run if I add in a main effect of age on the mean. However, this model gives me negative estimates, and I’m not sure if that’s reflective of something wrong with my code. Any help is appreciated!
Thanks!
Amanda
Looks OK
While it's true you obtained some negative point estimates from the second model, that's not necessarily bad. Your parameters
a11
,c11
, ande11
represent what the loading (path coefficient) onto (respectively) A, C, and E will be when age equals zero. Your parametersaM11
,cM11
, andeM11
represent how much their corresponding loading changes for a 1-unit change in age. Note that the resulting loadings themselves are ambiguous with respect to sign. For instance, the A variance component is(a+ D%*%aM) %*% t(a+ D%*%aM)
, which in this case is equivalent to squaring a scalar, so it will always be non-negative.Log in or register to post comments
In reply to Looks OK by AdminRobK
Thanks
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