Moderated polynomial regression

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Alejandro Hermida

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Jun 5, 2020, 10:35:47 AM6/5/20

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Hi!

I am trying to run a moderated polynomial regression model similar to Ilmarinen et al., 2017. In their study, they obtain the interaction terms by multiplying the parameters estimated from a polynomial regression with the moderating variables. I tried to do something similar using lavaan and receive the following error:

"unknown label(s) in variable definition(s): Z"

A reduced example of how I specified the model is:

Outcome1 ~ b1*X + b2*Y + b3*Xsq + b4*XY + b5*Ysq

# derived variables: Moderated parameters

b1M := b1*Z

...

# derived variables: congruence and incongruence parameters

a1 := b1 + b2

...

# derived variables: congruence and incongruence moderated parameters

a1M := b1M + b2M

...

Is this because I am trying to estimate the moderated parameters using both observed and estimated parameters at the same time?

I would very much appreciate your help!

Thank you,

Alejandro

Terrence Jorgensen

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Jun 5, 2020, 4:32:19 PM6/5/20

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"unknown label(s) in variable definition(s): Z"

Is this because I am trying to estimate the moderated parameters using both observed and estimated parameters at the same time?

No, it is because there is no parameter in your syntax labeled "Z"

Terrence D. Jorgensen

Assistant Professor, Methods and Statistics

Research Institute for Child Development and Education, the University of Amsterdam