Principles of Data Visualization and Introduction to ggplot2

I have provided you with data about the 5,000 fastest growing companies in the US, as compiled by Inc. magazine. lets read this in:

library(tidyverse)
library(ggplot2)
library(scales)

inc <- read.csv("https://raw.githubusercontent.com/charleyferrari/CUNY_DATA_608/master/module1/Data/inc5000_data.csv", header= TRUE, stringsAsFactors = TRUE)

And lets preview this data:

head(inc)
##   Rank                         Name Growth_Rate   Revenue
## 1    1                         Fuhu      421.48 1.179e+08
## 2    2        FederalConference.com      248.31 4.960e+07
## 3    3                The HCI Group      245.45 2.550e+07
## 4    4                      Bridger      233.08 1.900e+09
## 5    5                       DataXu      213.37 8.700e+07
## 6    6 MileStone Community Builders      179.38 4.570e+07
##                       Industry Employees         City State
## 1 Consumer Products & Services       104   El Segundo    CA
## 2          Government Services        51     Dumfries    VA
## 3                       Health       132 Jacksonville    FL
## 4                       Energy        50      Addison    TX
## 5      Advertising & Marketing       220       Boston    MA
## 6                  Real Estate        63       Austin    TX
summary(inc)
##       Rank                          Name       Growth_Rate     
##  Min.   :   1   (Add)ventures         :   1   Min.   :  0.340  
##  1st Qu.:1252   @Properties           :   1   1st Qu.:  0.770  
##  Median :2502   1-Stop Translation USA:   1   Median :  1.420  
##  Mean   :2502   110 Consulting        :   1   Mean   :  4.612  
##  3rd Qu.:3751   11thStreetCoffee.com  :   1   3rd Qu.:  3.290  
##  Max.   :5000   123 Exteriors         :   1   Max.   :421.480  
##                 (Other)               :4995                    
##     Revenue                                  Industry      Employees      
##  Min.   :2.000e+06   IT Services                 : 733   Min.   :    1.0  
##  1st Qu.:5.100e+06   Business Products & Services: 482   1st Qu.:   25.0  
##  Median :1.090e+07   Advertising & Marketing     : 471   Median :   53.0  
##  Mean   :4.822e+07   Health                      : 355   Mean   :  232.7  
##  3rd Qu.:2.860e+07   Software                    : 342   3rd Qu.:  132.0  
##  Max.   :1.010e+10   Financial Services          : 260   Max.   :66803.0  
##                      (Other)                     :2358   NA's   :12       
##             City          State     
##  New York     : 160   CA     : 701  
##  Chicago      :  90   TX     : 387  
##  Austin       :  88   NY     : 311  
##  Houston      :  76   VA     : 283  
##  San Francisco:  75   FL     : 282  
##  Atlanta      :  74   IL     : 273  
##  (Other)      :4438   (Other):2764

Think a bit on what these summaries mean. Use the space below to add some more relevant non-visual exploratory information you think helps you understand this data:

The summary function provides exactly what is needed in terms of summary statistics. The function showed only the variable type for the categorical variables, so I added StringAsFactors =TRUE when building the data frames

The function provides an overall glimpse via descriptive statistics for the columns in the dataset. As we can see from the summary the dataset is dominated by IT services, followed by Business Products and Services and Advertising and Marketing companies.

# We can also use str overview of inc data frame
str(inc)
## 'data.frame':    5001 obs. of  8 variables:
##  $ Rank       : int  1 2 3 4 5 6 7 8 9 10 ...
##  $ Name       : Factor w/ 5001 levels "(Add)ventures",..: 1770 1633 4423 690 1198 2839 4733 1468 1869 4968 ...
##  $ Growth_Rate: num  421 248 245 233 213 ...
##  $ Revenue    : num  1.18e+08 4.96e+07 2.55e+07 1.90e+09 8.70e+07 ...
##  $ Industry   : Factor w/ 25 levels "Advertising & Marketing",..: 5 12 13 7 1 20 10 1 5 21 ...
##  $ Employees  : int  104 51 132 50 220 63 27 75 97 15 ...
##  $ City       : Factor w/ 1519 levels "Acton","Addison",..: 391 365 635 2 139 66 912 1179 131 1418 ...
##  $ State      : Factor w/ 52 levels "AK","AL","AR",..: 5 47 10 45 20 45 44 5 46 41 ...

Another important is to check the missing values since they might affect or skew our visualizations.

colSums(is.na(inc))
##        Rank        Name Growth_Rate     Revenue    Industry   Employees 
##           0           0           0           0           0          12 
##        City       State 
##           0           0

Let’s take a look at the top five industries with the highest growth rates.

top5 <-inc%>%
  group_by(Industry)%>%
  summarize(Avg_growth=mean(Growth_Rate))%>%
  top_n(5,Avg_growth)%>%
  arrange(desc(Avg_growth))

top5
## # A tibble: 5 x 2
##   Industry                     Avg_growth
##   <fct>                             <dbl>
## 1 Energy                             9.60
## 2 Consumer Products & Services       8.78
## 3 Real Estate                        7.75
## 4 Government Services                7.24
## 5 Advertising & Marketing            6.23

Let’s get the top 5 cities in America with the 1000 fastest growing companies

top_5_cities <- inc %>% arrange(desc(Growth_Rate)) %>% head(1000) %>% count(City, sort = TRUE) %>% head(5)
top_5_cities
##            City  n
## 1      New York 35
## 2 San Francisco 26
## 3       Chicago 20
## 4        Austin 19
## 5       Atlanta 17

We can Also check how many state codes are there in the data set.

unique(unlist(inc$State))
##  [1] CA VA FL TX MA TN UT RI SC DC NJ OH WA ME NY CO GA IL AZ NC MD MN OK PA CT
## [26] IN MS WI WY MI MO KS OR NE AL HI NV IA KY ID AK LA DE AR NH VT NM SD ND PR
## [51] MT WV
## 52 Levels: AK AL AR AZ CA CO CT DC DE FL GA HI IA ID IL IN KS KY LA MA ... WY

We see 52 codes, the 50 states plus DC and Puerto Rico. Next we can do same for Industry column to see how many they are there and if they’re duplicate.

unique(unlist(inc$Industry))
##  [1] Consumer Products & Services Government Services         
##  [3] Health                       Energy                      
##  [5] Advertising & Marketing      Real Estate                 
##  [7] Financial Services           Retail                      
##  [9] Software                     Computer Hardware           
## [11] Logistics & Transportation   Food & Beverage             
## [13] IT Services                  Business Products & Services
## [15] Education                    Construction                
## [17] Manufacturing                Telecommunications          
## [19] Security                     Human Resources             
## [21] Travel & Hospitality         Media                       
## [23] Environmental Services       Engineering                 
## [25] Insurance                   
## 25 Levels: Advertising & Marketing ... Travel & Hospitality

We see 25 different industry categories and none of them overlap.

Question 1

Create a graph that shows the distribution of companies in the dataset by State (ie how many are in each state). There are a lot of States, so consider which axis you should use. This visualization is ultimately going to be consumed on a ‘portrait’ oriented screen (ie taller than wide), which should further guide your layout choices.

# Prepare the data for plotting

data <- inc %>% 
    group_by(State) %>% 
    tally() %>%
  rename(count = n) %>%
  arrange(desc(count))

#plot our data
g <- ggplot(data, aes(x = reorder(State, count), y = count)) 
g <- g + geom_bar(stat = "identity", fill = 'dodgerblue1') + coord_flip() 
g <- g + ggtitle("Distribution of 5,000 Fastest Growing Companies")
g <- g + labs(subtitle = "by state", x = "state", y = "company count")
g <- g + theme(plot.title = element_text(hjust = 0.5), plot.subtitle = element_text(hjust = 0.5))
g

California, Texas, and New York appear to have the 3 fastest growing companies in the US.

Quesiton 2

Lets dig in on the state with the 3rd most companies in the data set. Imagine you work for the state and are interested in how many people are employed by companies in different industries. Create a plot that shows the average and/or median employment by industry for companies in this state (only use cases with full data, use R’s complete.cases() function.) In addition to this, your graph should show how variable the ranges are, and you should deal with outliers.

# First let's find state with third most companies (our data is already ordered in descendant, therefore the 3rd row)
state3rd <- data[3,"State"]
state3rd
## # A tibble: 1 x 1
##   State
##   <fct>
## 1 NY
# filter 3rd ranked state only   
data2 <- inc[complete.cases(inc),] %>%
  inner_join(state3rd, by = "State")

# Calculate the mean employees by industry
means <- aggregate(Employees ~ Industry, data2, mean)

# Calculate the maximum average employee no.
means_max <- max(means$Employees)

# prepare plot data: box plots (with outliers removed)
g <- ggplot(data2, aes(x = reorder(Industry,Employees,mean), y = Employees))
g <- g + geom_boxplot(outlier.shape = NA, show.legend=F) + coord_flip()
g <- g + labs(x = "industry", y = "employees", title="Mean Employee Size by Industry")
g <- g + labs(subtitle = "with boxplots")
g <- g + geom_point(data = means, aes(x=Industry, y=Employees), color='darkred', size = 2)
g <- g + theme(plot.title = element_text(hjust = 0.5), plot.subtitle = element_text(hjust = 0.5))

# plot data, linear scale
g <- g +  scale_y_continuous(limits = c(0,means_max), breaks = seq(0, means_max, 200))
g

We can see from the graph that the mean data are highly skewed, that is there is an outlier employee count in the Business Products & Services industry that is almost 2 times greater than the second ranked industry, Consumer Products & Services. i.e. more than 100%. We can visualize the data on a logarithmic scale to scale everything down.

# plot data, log scale
g <- g + scale_y_log10(limits = c(1, means_max))
g <- g + labs(caption = "(logarithmic scale spacing)")
g <- g + theme(plot.caption = element_text(size = 8))
g

Question 3

Now imagine you work for an investor and want to see which industries generate the most revenue per employee. Create a chart that makes this information clear. Once again, the distribution per industry should be shown.

# Filter by Most Revenue per employee by industry
revenue.industry <- inc %>%
  filter(State== "NY") %>% 
  group_by(Industry) %>% 
  summarise(avg_revenue = mean(Revenue))


# NOw since we have the filtered data, let's put it into graph to see visualization

ggplot(revenue.industry, aes(x=reorder(Industry, avg_revenue), y=avg_revenue))+geom_bar(stat="identity", fill="#03DAC5")+coord_flip()+labs(title="Average Revenue per Employee by industry in NY", x="Industry", y="Average Revenue per Employee")

Conclusion

According to visualizations from Question 1, California has the most number of companies in United States. In Question 2 we dug in on the state with the 3rd most companies in the data set which is New York, and we used a box plot to show the average and/or median employment by industry for companies in NY. Box plots help visualize the distribution of quantitative values in a field. They are also valuable for comparisons across different categorical variables or identifying outliers, if either of those exist in a dataset. Finally to check the average revenue per employee by different industry in NY, we again created bar chart and found that consumer products & services has the highest average revenue per employee while IT services and business products & services are the next highest. Eduction and government services has the least average revenue per employee in NY.