R/standardized.coefficients.R

In sem1: Structural Equation Models

# last modified 24 May 2009 by Adam Kramer (original by J. Fox)
# last modified 24 May 2009 by J. Fox

standardized.coefficients <- function (object, digits = 5, oneheaded=TRUE, twoheaded=TRUE)
{
	if (!oneheaded && !twoheaded) {
		stop("No coefficients requested.")
	}
	old.digits <- options(digits = digits)
	on.exit(options(old.digits))
	P <- object$P
	A <- object$A
	t <- object$t
	par <- object$coeff
	par.posn <- object$par.posn
	IAinv <- solve(diag(nrow(A)) - A)
	C <- IAinv %*% P %*% t(IAinv)
	ram <- object$ram
	par.names <- rep(" ", nrow(ram))
	for (i in 1:t) {
		which.par <- ram[, 4] == i
		ram[which.par, 5] <- par[i]
		par.names[which.par] <- names(par)[i]
	}
	coeff <- ram[, 5]
	if (oneheaded) {
		one.head <- ram[, 1] == 1
		coeff[one.head] <- coeff[one.head] * sqrt(diag(C[ram[one.head, 3], ram[one.head,
						3], drop=FALSE])/diag(C[ram[one.head, 2], ram[one.head, 2], drop=FALSE]))
	}
	if (twoheaded) {
		two.head <- ram[, 1] == 2
		coeff[two.head] <- coeff[two.head] / sqrt(diag(C[ram[two.head, 3], ram[two.head,
						3], drop=FALSE])*diag(C[ram[two.head, 2], ram[two.head, 2], drop=FALSE]))
	}
	var.names <- rownames(A)
	par.code <- paste(var.names[ram[, 2]], c("<---",
			"<-->")[ram[, 1]], var.names[ram[, 3]])
	coeff <- data.frame(par.names, coeff, par.code)
	colnames(coeff) <- c(" ", "Std. Estimate", " ")
	if (oneheaded && twoheaded) {
		coeff
	}
	else if (oneheaded) {
		coeff[one.head,]
	}
	else {
		coeff[two.head,]
	}
}

#standardized.coefficients <- function (object, digits = 5) 
#{
#    old.digits <- options(digits = digits)
#    on.exit(options(old.digits))
#    P <- object$P
#    A <- object$A
#    t <- object$t
#    par <- object$coeff
#    par.posn <- object$par.posn
#    IAinv <- solve(diag(nrow(A)) - A)
#    C <- IAinv %*% P %*% t(IAinv)
#    ram <- object$ram
#    par.names <- rep(" ", nrow(ram))
#    for (i in 1:t) {
#        which.par <- ram[, 4] == i
#        ram[which.par, 5] <- par[i]
#        par.names[which.par] <- names(par)[i]
#    }
#    one.head <- ram[, 1] == 1
#    coeff <- ram[one.head, 5]
#    coeff <- coeff * sqrt(diag(C[ram[one.head, 3], ram[one.head, 
#        3], drop=FALSE])/diag(C[ram[one.head, 2], ram[one.head, 2], drop=FALSE]))
#    var.names <- rownames(A)
#    par.code <- paste(var.names[ram[one.head, 2]], c("<---", 
#        "<-->")[ram[one.head, 1]], var.names[ram[one.head, 3]])
#    coeff <- data.frame(par.names[one.head], coeff, par.code)
#    names(coeff) <- c(" ", "Std. Estimate", " ")
#    print(coeff, rowlab = rep(" ", nrow(coeff)), right = FALSE)
#}

std.coef <- function (...){
    standardized.coefficients(...)
    }