如何使用 R 中的 lavaan 包在 SEM 模型中模拟分类 IV 和连续调节器(通过 CFA 创建)之间的交互?

How to model an interacton between a categorical IV and a continous moderator (created through a CFA) in a SEM model using the lavaan package in R?

如何使用 R 中的 lavaan 包在 SEM 模型中对分类自变量和连续调节器(通过 CFA 创建)之间的相互作用进行建模?

特别是,在我的真实数据集中,我基本上对在 SEM 中重新创建双向方差分析很感兴趣,并且还想包含一个调节变量来测试每个因子变量。

示例数据和问题:

### load packages: ###
library(dplyr)
library(lavaan)
library(car)
library(psychTools)

### Create some data: ###

# Dependent variable: Taken example data from psychTools
DV1 <- bfi$A1 # item 1 
DV2 <- bfi$A2 # item 2
DV3 <- bfi$A3 # item 3

# Moderating variable: Taken example data from psychTools
MOD1 <- bfi$C1 # item 1
MOD2 <- bfi$C2 # item 2
MOD3 <- bfi$C3 # item 3

# Create example factor variables
x1 <- c("A","B")
x2 <- c("C","D")
set.seed(1)
FAC1 <- as.factor(sample(x1, 200, replace = TRUE)) # Factor 1, with two levels "A" and "B"
FAC2 <- as.factor(sample(x2, 200, replace = TRUE)) # Factor 2, with two levels "C" and "D"
FAC12 <- interaction(FAC1,FAC2) # Factor 12, interaction of FAC1 and FAC2, with four levels "A.C" "B.C" "A.D" "B.D"

# Combine to data frame
StudyData <- data.frame(DV1,DV2,DV3, 
                        MOD1,MOD2,MOD3,
                        FAC1, FAC2, FAC12)

### Make all categorical variables numeric for use in SEM (orthogonal contrast coded as in ANOVA): ###

StudyData$FAC1 <- recode(StudyData$FAC1, "c('A')='-1';
                                          c('B')='1'")
StudyData$FAC1 <- as.numeric(levels(StudyData$FAC1))[StudyData$FAC1]

StudyData$FAC2 <- recode(StudyData$FAC2, "c('C')='-1';
                                          c('D')='1'")
StudyData$FAC2 <- as.numeric(levels(StudyData$FAC2))[StudyData$FAC2]

StudyData$FAC12 <- recode(StudyData$FAC12, "c('A.D','B.C')='-1';
                                          c('A.C','B.D')='1'")
StudyData$FAC12 <- as.numeric(levels(StudyData$FAC12))[StudyData$FAC12]

### SEM Model One: ###
Model.one <- '
# cfa
DV =~ DV1 + DV2 + DV3
MOD =~ MOD1 + MOD2 + MOD3
# regressions
DV ~ FAC1 + FAC2 + FAC12
'

Modelone <- sem(Model.one, StudyData, estimator="MLM", effect.coding=TRUE, meanstructure=TRUE) 
summary(Modelone)
fitMeasures(Modelone, c("chisq","cfi","rmsea","srmr","nfi","gfi"))

### SEM Model Two: ###
Model.two <- '
# cfa
DV =~ DV1 + DV2 + DV3
MOD =~ MOD1 + MOD2 + MOD3
# regressions
DV ~ FAC1 + FAC1:MOD + FAC2 + FAC12
'

Modeltwo <- sem(Model.two, StudyData, estimator="MLM", effect.coding=TRUE, meanstructure=TRUE) 
summary(Modeltwo)
fitMeasures(Modeltwo, c("chisq","cfi","rmsea","srmr","nfi","gfi"))

### SEM Model Three: ###
Model.three <- '
# cfa
DV =~ DV1 + DV2 + DV3
MOD =~ MOD1 + MOD2 + MOD3
# regressions
DV ~ FAC1:MOD
'

Modelthree <- sem(Model.three, StudyData, estimator="MLM", effect.coding=TRUE, meanstructure=TRUE) 
summary(Modelthree)
fitMeasures(Modelthree, c("chisq","cfi","rmsea","srmr","nfi","gfi")

型号一 运行 没问题。我可以在 SEM 环境中 运行 我的“方差分析”。

但是,当我想要 运行 模型二时,其中包括 FAC1 和 MOD 之间的交互项(通过 SEM 模型中的 CFA 创建),我收到错误消息:

"lavaan 警告:估计参数 (vcov) 的方差-协方差矩阵似乎不是正定的!最小特征值 (= -3.458498e-20) 小于零。这可能是一个症状该模型未被识别。"

问题:

  1. 是否无法在中创建 factor:continuous 交互 以这种方式熔岩?
  2. 是否有任何变通办法以及如何解决? (例如,提取 CFA 期间为 MOD 计算的值 并在 SEM 之外计算 FAC1:MOD 交互,然后重新使用 SEM 的路径分析(回归)部分中的变量)
  3. Mplus 可以在不需要变通方法的情况下做到这一点吗?

编辑:添加了带有精益交互模型的“SEM 模型三”以响应评论。

我在 CrossValidated 上发布了这个重复问题的答案:

https://stats.stackexchange.com/questions/552623/how-to-model-an-interacton-between-a-categorical-iv-and-a-continous-moderator-c