Plot the accuracy of a model trained in R with caret through time

plot_temporal_accuracy.R

library(plyr)

data <- read.table("rdata-10pct-1973-1999.dat",sep = " ", header = TRUE, na.strings="NULL",
    colClasses=c(DATE="character",GVKEY="character",MONTH="character"))

x <- data[1:6]
y <- factor(data$LABEL)

preds.train <- predict(mdl,x)
data$preds <- as.numeric(levels(preds.train))[preds.train]
data$correct <- (data$LABEL*data$preds+1)/2

mean(data$correct)

res <- ddply(data,"DATE",summarise,mean=mean(correct),size=length(correct))

plot(res$DATE,res$mean)

ggplot(data = res, aes( DATE, mean )) + geom_point() + scale_x_discrete(breaks = c("197301","198001","199001","199912"))