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I am trying to compare two groups of children and test whether executive function (EF) is a significant predictor of reasoning (CR) (and I also include other covariates) using SEM and the lavaan package in R.

  1. Am I correctly doing that comparison with this code?
  2. How do I interpret the lengthy output?
  3. Is the only way to compare whether or not the regression coefficients are significantly different between groups is to compare two models with and without constraining the regressions to be equal?

Attempt 1:

mod1= ' 
CR =~ v1 +  v2
EF =~ ef1 + ef2 + ef3 + ef4 + ef5
CR ~  c(a1, a2)*v3 + c(b1,b2)*v4 + c(c1,c2)*v5 + c(d1, d2)*EF  
diff.a1a2 := a1 - a2 
diff.b1b2 := b1 - b2 
diff.c1c2 := c1 - c2 
diff.d1d2 := d1 - d2 '
fitnew<- sem(mod1, data=datamicescaled, 
             std.lv =T, group = "age.group",estimator = "MLR", missing = "fiml")
summary(fitnew, fit.measures=TRUE, standardized=TRUE)

Output 1:

Defined Parameters:
                   Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
    diff.a1a2        -0.049    0.509   -0.095    0.924   -0.063   -0.170
    diff.b1b2         0.948    4.497    0.211    0.833    0.020    0.026
    diff.c1c2         1.023    2.425    0.422    0.673    0.250    0.293
    diff.d1d2         0.945    4.823    0.196    0.845    0.070    0.070

Attempt 2:

mod2= ' 
CR =~ v1 +  v2 + v3
EF =~ ef1 + ef2 + ef3 + ef4 + ef5
CR ~  v4 + v5 + v6 + EF  '

fit2<- sem(mod2, data=datamicescaled, 
             std.lv =T, group = "age.group",estimator = "MLR", missing = "fiml", group.equal = c"regressions)
summary(fit2, fit.measures=TRUE, standardized=TRUE)

Thank you in advance for any help. I have been talking myself into circles all day, and I would really appreciate any input!

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1 回答 1

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我不确定我是否完全理解你的问题。尽管如此，这是我的答案（希望它有所帮助）：

如果要比较组，则必须在逐步限制模型的情况下进行不变性分析，并且只有当您将约束系数限制为跨组相等时，才探测模型变得更糟，那么您可以开始估计系数对于每个组。

这个视频很有用

于 2021-02-04T19:50:56.113 回答