The Match Reports from the official FIFA 2018 World Cup website provide excellent sources of secondary data.
I have used these data to profile ball in play times and fouls identified by referees. I have used the
ggplot library in RStudio to do this. I used
geom_label_repel() for my text labels. I have used a Loess Regresssion to smooth the data series.
Ball in Play
I have posted my code and other material in a GitHub repository RefereeingWC18.