让我们首先重写您的测试用例，使其同时包含一个具有随机效应的模型 ( clmm) 和一个没有随机效应的模型 ( clm)，两者都来自ordinal包。这将允许我们检查extract.clmm我们将要编写的函数是否产生格式与包中现有extract.clm函数兼容的结果texreg：
library("ordinal")
library("texreg")
d <- data.frame(wine)
result.clmm <- clmm(rating ~ 1 + temp + contact + (1 + temp|judge), data = d)
result.clm <- clm(rating ~ 1 + temp + contact, data = d)
现有clm的泛型extract函数方法texreg如下所示，我们可以将其用作编写clmm方法的模板，因为两种对象类型的结构都类似：
# extension for clm objects (ordinal package)
extract.clm <- function(model, include.thresholds = TRUE, include.aic = TRUE,
include.bic = TRUE, include.loglik = TRUE, include.nobs = TRUE, ...) {
s <- summary(model, ...)
tab <- s$coefficients
thresh <- tab[rownames(tab) %in% names(s$aliased$alpha), , drop = FALSE]
threshold.names <- rownames(thresh)
threshold.coef <- thresh[, 1]
threshold.se <- thresh[, 2]
threshold.pval <- thresh[, 4]
beta <- tab[rownames(tab) %in% names(s$aliased$beta), , drop = FALSE]
beta.names <- rownames(beta)
beta.coef <- beta[, 1]
beta.se <- beta[, 2]
beta.pval <- beta[, 4]
if (include.thresholds == TRUE) {
names <- c(beta.names, threshold.names)
coef <- c(beta.coef, threshold.coef)
se <- c(beta.se, threshold.se)
pval <- c(beta.pval, threshold.pval)
} else {
names <- beta.names
coef <- beta.coef
se <- beta.se
pval <- beta.pval
}
n <- nobs(model)
lik <- logLik(model)[1]
aic <- AIC(model)
bic <- BIC(model)
gof <- numeric()
gof.names <- character()
gof.decimal <- logical()
if (include.aic == TRUE) {
gof <- c(gof, aic)
gof.names <- c(gof.names, "AIC")
gof.decimal <- c(gof.decimal, TRUE)
}
if (include.bic == TRUE) {
gof <- c(gof, bic)
gof.names <- c(gof.names, "BIC")
gof.decimal <- c(gof.decimal, TRUE)
}
if (include.loglik == TRUE) {
gof <- c(gof, lik)
gof.names <- c(gof.names, "Log Likelihood")
gof.decimal <- c(gof.decimal, TRUE)
}
if (include.nobs == TRUE) {
gof <- c(gof, n)
gof.names <- c(gof.names, "Num.\ obs.")
gof.decimal <- c(gof.decimal, FALSE)
}
tr <- createTexreg(
coef.names = names,
coef = coef,
se = se,
pvalues = pval,
gof.names = gof.names,
gof = gof,
gof.decimal = gof.decimal
)
return(tr)
}
setMethod("extract", signature = className("clm", "ordinal"),
definition = extract.clm)
对象的第一个区别clmm是系数等不是存储在summary(model)$aliased$alphaand下summary(model)$aliased$beta，而是直接存储在summary(model)$alphaand下summary(model)$beta。
我们需要做的第二件事是为组数和随机方差添加拟合优度元素。
组的数量显然存储在 下summary(model)$dims$nlev.gf，具有不同条件变量的多个条目。所以这很容易。
随机方差没有存储在任何地方，所以我们需要在包的源代码中ordinal查找它。我们可以看到该print.summary.clmm函数使用了一个内部辅助函数formatVC来打印方差。该函数包含在同一个R脚本中，基本上只是进行格式化并调用另一个名为varcov（也包含在同一文件中）的内部辅助函数来计算方差。反过来，该函数计算 的转置叉积model$ST以获得方差。我们可以直接在extract.clmm函数的 GOF 块中简单地做同样的事情，例如，使用diag(s$ST[[1]] %*% t(s$ST[[1]]))对于第一个随机效应。我们只需要确保我们对所有随机效果都这样做，这意味着我们需要将它放在一个循环中并用[[1]]像[[i]].
该函数的最终clmm方法extract可能如下所示：
# extension for clmm objects (ordinal package)
extract.clmm <- function(model, include.thresholds = TRUE,
include.loglik = TRUE, include.aic = TRUE, include.bic = TRUE,
include.nobs = TRUE, include.groups = TRUE, include.variance = TRUE, ...) {
s <- summary(model, ...)
tab <- s$coefficients
thresh <- tab[rownames(tab) %in% names(s$alpha), ]
threshold.names <- rownames(thresh)
threshold.coef <- thresh[, 1]
threshold.se <- thresh[, 2]
threshold.pval <- thresh[, 4]
beta <- tab[rownames(tab) %in% names(s$beta), ]
beta.names <- rownames(beta)
beta.coef <- beta[, 1]
beta.se <- beta[, 2]
beta.pval <- beta[, 4]
if (include.thresholds == TRUE) {
cfnames <- c(beta.names, threshold.names)
coef <- c(beta.coef, threshold.coef)
se <- c(beta.se, threshold.se)
pval <- c(beta.pval, threshold.pval)
} else {
cfnames <- beta.names
coef <- beta.coef
se <- beta.se
pval <- beta.pval
}
gof <- numeric()
gof.names <- character()
gof.decimal <- logical()
if (include.loglik == TRUE) {
lik <- logLik(model)[1]
gof <- c(gof, lik)
gof.names <- c(gof.names, "Log Likelihood")
gof.decimal <- c(gof.decimal, TRUE)
}
if (include.aic == TRUE) {
aic <- AIC(model)
gof <- c(gof, aic)
gof.names <- c(gof.names, "AIC")
gof.decimal <- c(gof.decimal, TRUE)
}
if (include.bic == TRUE) {
bic <- BIC(model)
gof <- c(gof, bic)
gof.names <- c(gof.names, "BIC")
gof.decimal <- c(gof.decimal, TRUE)
}
if (include.nobs == TRUE) {
n <- nobs(model)
gof <- c(gof, n)
gof.names <- c(gof.names, "Num.\ obs.")
gof.decimal <- c(gof.decimal, FALSE)
}
if (include.groups == TRUE) {
grp <- s$dims$nlev.gf
grp.names <- paste0("Groups (", names(grp), ")")
gof <- c(gof, grp)
gof.names <- c(gof.names, grp.names)
gof.decimal <- c(gof.decimal, rep(FALSE, length(grp)))
}
if (include.variance == TRUE) {
var.names <- character()
var.values <- numeric()
for (i in 1:length(s$ST)) {
variances <- diag(s$ST[[i]] %*% t(s$ST[[i]]))
var.names <- c(var.names, paste0("Variance: ", names(s$ST)[[i]], ": ",
names(variances)))
var.values <- c(var.values, variances)
}
gof <- c(gof, var.values)
gof.names <- c(gof.names, var.names)
gof.decimal <- c(gof.decimal, rep(TRUE, length(var.values)))
}
tr <- createTexreg(
coef.names = cfnames,
coef = coef,
se = se,
pvalues = pval,
gof.names = gof.names,
gof = gof,
gof.decimal = gof.decimal
)
return(tr)
}
setMethod("extract", signature = className("clmm", "ordinal"),
definition = extract.clmm)
您可以在运行时执行代码，并且texreg应该能够从clmm对象创建表，包括随机方差。我会将此代码添加到下一个texreg版本中。
您可以将其应用于您的示例，如下所示：
screenreg(list(result.clmm, result.clm), single.row = TRUE)
结果clmm与clm对象兼容，正如您在输出中看到的那样：
==================================================================
Model 1 Model 2
------------------------------------------------------------------
tempwarm 3.07 (0.61) *** 2.50 (0.53) ***
contactyes 1.83 (0.52) *** 1.53 (0.48) **
1|2 -1.60 (0.69) * -1.34 (0.52) **
2|3 1.50 (0.60) * 1.25 (0.44) **
3|4 4.22 (0.82) *** 3.47 (0.60) ***
4|5 6.11 (1.02) *** 5.01 (0.73) ***
------------------------------------------------------------------
Log Likelihood -81.55 -86.49
AIC 181.09 184.98
BIC 201.58 198.64
Num. obs. 72 72
Groups (judge) 9
Variance: judge: (Intercept) 1.16
Variance: judge: tempwarm 0.03
==================================================================
*** p < 0.001, ** p < 0.01, * p < 0.05
如果需要，您可以使用参数include.variances == FALSE并include.groups == FALSE关闭差异和组大小的报告。