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  • I'm running the same data for SEM but getting two different results

    I have given my data set to my professor, and when he runs the SEM, he gets constraints with values, whereas when I run the same data,
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    I get constraints that are 0. What am I missing?
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  • #2
    Originally posted by Charmain Farrar View Post
    I have given my data set to my professor, and when he runs the SEM, he gets constraints with values, whereas when I run the same data, I get constraints that are 0. What am I missing?
    Do you mean constants that are zero? I'm not sure which is yours and which your professor's, but on the left-hand side, the constants are all free to be estimated; on the right-hand side, the constants are all constrained to be zero, and so that's why they are all zero.

    If you mean constraints, well the left-hand side doesn't impose any other than for one factor loading per latent variable for identification. It's equivalent to (names of latent factors abbreviated)
    Code:
    import excel "Copy of CSWS - ERBTS_May 25, 2024.xlsx", sheet(Sheet0) firstrow clear
    
    rename *, lower
    
    sem ///
        (ab ad ae aq ar <- I) ///
        (az ba bc bd be <- A) ///
        (bf bg bi bk bl <- M), ///
            method(mlmv)
    And the one on the right-hand side is equivalent to
    Code:
    sem ///
        (ab ad ae aq ar <- I, noconstant) ///
        (az ba bc bd be <- A, noconstant) ///
        (bf bg bi bk bl <- M, noconstant), ///
            method(mlmv) covstructure(_LEx, diagonal)
    By the way, it's not clear why the left-hand side specifies covstructure(_lexogenous, diagonal), but then goes right ahead and specifies all of the latent factors' covariances anyway.

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