influence.SEM (version 2.3)

fitinfluence: Case influence on model fit.

Description

This function evaluate the case's effect on a user-defined fit index.

Usage

fitinfluence(index, model, data, ...)

Arguments

index

A model fit index.

model

A description of the user-specified model using the lavaan model syntax. See lavaan for more information.

data

A data frame containing the observed variables used in the model. If any variables are declared as ordered factors, this function will treat them as ordinal variables.

…

Additional parameters for sem function.

Value

Returns a list:

Dind

a data.frame of case influence.

Oind

observed fit indices.

Details

For each case evaluate the influence on one or more fit indices: the difference between the chosen fit index calculated for the SEM target model $M$ and the same index computed for the SEM model $M_{(i)}$ excluding case $i$.

References

Pek, J., MacCallum, R.C. (2011). Sensitivity Analysis in Structural Equation Models: Cases and Their Influence. Multivariate Behavioral Research, 46, 202-228.

Examples

# NOT RUN {
## not run: this example take several minutes
data("PDII")
model <- "
  F1 =~ y1+y2+y3+y4
"

# fit0 <- sem(model, data=PDII)
# FI <- fitinfluence("cfi",model,data=PDII)
# plot(FI$Dind,pch=19)

## not run: this example take several minutes
## an example in which the deletion of a case yelds a solution 
## with negative estimated variances
model <- "
  F1 =~ x1+x2+x3
  F2 =~ y1+y2+y3+y4
  F3 =~ y5+y6+y7+y8
"

# fit0 <- sem(model, data=PDII)
# FI <- fitinfluence(c("tli","rmsea"),model,PDII)
# explore.influence(FI$Dind$tli)
# explore.influence(FI$Dind$rmsea)
# }