Chicago Employee Salary Box plot

Data

This plot uses the chi_emps data set of the gcubed package. The original source of the data is the City of Chicago’s Data Portal⁷.

First we identify the departments with 500 or more employees. Then we restrict the data set to those employees that are salaried⁸.

library(gcubed)
library(dplyr)

dept_counts <- table(chi_emps$Department)
large_dept_counts <- dept_counts[dept_counts >= 500 ]
large_dept_names <- names(large_dept_counts)

large_depts <- chi_emps[chi_emps$Department %in% large_dept_names & chi_emps$SalHour == "Salary",]


sorted_depts <- group_by(large_depts, Department) %>% 
  summarise(MedSal = median(AnnualSalary)) %>% 
  arrange(MedSal)

large_depts$Department <- factor(large_depts$Department, levels = sorted_depts$Department) 

Code for plot

This plot uses the geom_boxplot geometry.

library(ggplot2)
library(scales)


chi_dept500_boxplot <- ggplot(data = large_depts, aes(x = Department, y = AnnualSalary)) + 
  geom_boxplot() + 
  ggtitle("Salaries of Chicago City Govt Employees") + 
  theme(plot.title = element_text(size = 16, face = "bold", hjust = 0.5), 
        axis.text.x = element_text(angle = 90),
        axis.title.x=element_blank()) + 
  ylab("Annual Salary ($)") +
  scale_y_continuous(label = comma)

chi_dept500_boxplot 

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7. The data was current as of July 2019↩

8. This classification is not exactly the same as used in some of the other example plots using the same data set.↩