mod.indices calculates modification indices (score tests)
and estimated parameter changes for the fixed and constrained
parameters in a structural equation model fit by multinormal maximum likelihood.
# S3 method for objectiveML
modIndices(model, duplicated, deviance=NULL, ...)
# S3 method for msemObjectiveML
modIndices(model, ...)# S3 method for modIndices
print(x, n.largest=5, ...)
# S3 method for msemModIndices
print(x, ...)
# S3 method for modIndices
summary(object, round=2,
print.matrices=c("both", "par.change", "mod.indices"), ...)
# S3 method for msemModIndices
summary(object, ...)
modIndices returns an object of class modIndices with the following elements:
modification indices for the elements of the \(A\) matrix.
modification indices for the elements of the \(P\) matrix.
estimated parameter changes for the elements of the \(A\) matrix.
estimated parameter changes for the elements of the \(P\) matrix.
an object of class objectiveML or msemObjectiveML,
produced by the sem function.
an object of class modIndices or msemModIndices, produced by the
modIndices function.
number of modification indices to print in each of the \(A\) and \(P\) matrices of the RAM model.
number of places to the right of the decimal point in printing modification indices.
which matrices to print: estimated changes in the fixed parameters, modification indices, or both (the default).
for internal use.
arguments to be passed down.
John Fox jfox@mcmaster.ca and Michael Culbertson
Modification indices are one-df chi-square score (“Lagrange-multiplier”) test statistics for the fixed and constrained
parameters in a structural equation model. They may be regarded as an estimate of the improvement
in the likelihood-ratio chi-square statistic for the model if the corresponding parameter is
respecified as a free parameter. The modIndices function also estimates the change in the
value of a fixed or constrained parameter if the parameter is respecified as free. When several
parameters are set equal, modification indices and estimated changes are given for all but the first.
Modification indices and estimated parameter changes for currently free parameters are given as
NA.
The method employed is described in Saris, Satorra, and Sorbom (1987) and Sorbom (1989).
Sarris, W. E., Satorra, A., and Sorbom, D. (1987) The detection and correction of specification errors in structural equation models. Pp. 105--129 in Clogg, C. C. (ed.), Sociological Methodology 1987. American Sociological Association.
Sorbom, D. (1989) Model modification. Psychometrika 54, 371--384.
sem