Analyzing Survivor TV Show data

By Manuel Rademaker in R Data wrangling Data analysis Data visualization Tidyverse ggplot2

June 1, 2021

Description

The data this week comes from the survivorR R package by way of Daniel Oehm. survivoR is a collection of data sets detailing events across all 40 seasons of the US Survivor, including castaway information, vote history, immunity and reward challenge winners and jury votes.

Full details about the package and additional datasets available in the package are available on GitHub. The package is on CRAN as survivoR and can be installed for ALL the datasets, themes, etc via install.packages("survivoR").

Additional context/details about the Survivor TV show can be found on Wikipedia.

Data and variables

Taken from the Tidy Tuesday github repository. There are several data sets. I’m only going to examine the summary data set. Here is a variable description.

summary.csv

variable class description
season_name character Name of season
season integer Season number
location character Season geo location
country character Season country
tribe_setup character Tribe Setup
full_name character Full name of player
winner character Season winner
runner_ups character Runner ups
final_vote character Final vote for winner
timeslot character Time slot on TV
premiered double Premiered date
ended double Ended date
filming_started double Filming started date
filming_ended double Filming ended date
viewers_premier double Viewers (millions) at premier
viewers_finale double Viewers at finale
viewers_reunion double Viewers for reunion
viewers_mean double Viewers average
rank double Viewer ranking

Setup 

require(tidytuesdayR) # to easily get the tidy Tuesday data
require(tidyverse)    # includes dplyr, tidyr, ggplot, forcats etc.
require(visdat)       # for visualizing missing data (and data types)

I always take roughly the same approach when analyzing data that is already reasonably cleaned but not fully tidy yet. Depending on the type of data, additional steps are necessary and some others may be skipped.

Here are the steps I’m going to take:1

  1. Load data and get an understanding of the variables
  2. Develop interesting questions/hypotheses
  3. Tidy/clean
  4. Address questions/hypotheses

The goal is to come up with 2-3 insightful, publication ready visualizations.

Load data and get an understanding 

tt  <- tidytuesdayR::tt_load('2021-06-01')
summary <- tt$summary

dim(summary)
## [1] 40 19
vis_dat(summary)

Alright so there are 19 columns with 40 observations. There are some NAs but nothing unusual at first sight.

Develop questions / hypotheses

I don’t know the Survivor TV Show but I assume candidates have to survive some challenges and the last one standing is the winner – I guess?

There is information on how many watched the show and on the time it was aired. There is information on who one and whos the runner up. Lets quickly check if people appear twice.

summary %>% 
   count(winner) %>% 
   arrange(desc(n)) %>% 
   head(6)
## # A tibble: 6 x 2
##   winner      n
##   <chr>   <int>
## 1 Chris       2
## 2 Natalie     2
## 3 Sandra      2
## 4 Tony        2
## 5 Adam        1
## 6 Amber       1

Ok some appear more than one time.

What is tribe_setup?

summary %>% 
   count(tribe_setup)
## # A tibble: 31 x 2
##    tribe_setup                                                                 n
##    <chr>                                                                   <int>
##  1 "A schoolyard pick of two tribes of nine new players each; two elimina~     1
##  2 "A schoolyard pick of two tribes of nine new players, starting with th~     1
##  3 "Four tribes of five new players divided by ethnicity: African America~     1
##  4 "Four tribes of four new players divided by age and gender"                 1
##  5 "Nine pairs of new players, each with a pre-existing relationship, div~     1
##  6 "Three tribes of six  new players divided by primary attribute: \"braw~     1
##  7 "Three tribes of six new players divided by dominant perceived trait: ~     1
##  8 "Three tribes of six new players divided by primary attribute: \"brain~     1
##  9 "Three tribes of six new players divided by social class: \"white coll~     1
## 10 "Three tribes of six returning players"                                     1
## # ... with 21 more rows

I guess this somehow describes the how people are grouped to survive?

Just some quick questions that come to my mind

  1. Look at season ranking over seasons
  2. Number of viewers by season
  3. Season ranking and time slot ?
  4. Variables viewers_finale, viewers_premiere etc. seem to describe the number of viewers at different “stages” of the season. Will probably convert them to one variable and look at ranking by “stage”?
  5. Did the length of the filming (difference between filming_ended - filming_started) somehow change over time.

Address questions / hypotheses

Question 1: Season ranking over seasons 

ggplot(summary, aes(y = rank, x = season)) +
   geom_line() + 
   geom_point() + 
   scale_x_continuous(breaks = scales::breaks_width(5)) + 
   labs(
      title = "Viewer ranking by season",
      subtitle = "Lowest rank is best; hightest is worst",
      x = "Season",
      y = "Viewer ranking"
   )

Apparently viewers ranking generally goes up . Since a higher ranking is actually bad – I assume rank 1 is best – and people might be inclined to think that higher ranking is good, its probably good to explicitly mention that in the graph.

Question 2: Number of viewers 

summary %>% 
   pivot_longer(cols = viewers_premier:viewers_mean, 
                names_to = "stage",
                names_prefix = "viewers_",
                values_to = "viewers") %>% 
   ggplot(aes(x = season, y = viewers, color = fct_reorder(stage, -viewers))) + 
   geom_line() +
   geom_point() + 
   scale_x_continuous(breaks = scales::breaks_width(5)) +
   labs(
      title = "Number of viewers by season",
      subtitle = "In million viewers",
      x = "Season",
      y = "# Viewers",
      color = "Stage"
   )

Number of viewers generally declined over seasons. A pretty normal development. However, the absolute level is still decent with > 10 million viewers until about season 25. I think its also not surprising that the reunion show is typically less well-viewed than the rest.

Question 2.1: Correlation between ranking and number of viewers 

ggplot(summary, aes(x = viewers_mean, y = rank)) + 
   geom_point() + 
   geom_smooth(method = "lm") + 
   labs(
      title = "Season ranking vs. number of viewers",
      subtitle = "In million viewers",
      x = "Average number of viewers",
      y = "Ranking"
   )

As expected number of viewers is a pretty good predictor for the ranking. In fact lets run a simple linear regression.

summary(lm(rank ~ viewers_mean, data = summary))
## 
## Call:
## lm(formula = rank ~ viewers_mean, data = summary)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -8.4031 -2.6502 -0.3545  2.7108  8.4166 
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)    
## (Intercept)   40.8983     2.2870   17.88  < 2e-16 ***
## viewers_mean  -1.6136     0.1444  -11.18 2.93e-13 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 4.519 on 36 degrees of freedom
##   (2 observations deleted due to missingness)
## Multiple R-squared:  0.7763,	Adjusted R-squared:  0.7701 
## F-statistic: 124.9 on 1 and 36 DF,  p-value: 2.925e-13

Highly significant. A drop in average viewers per season of 1 million raises the expected rating by about 1.6 rating points.

Length of filming

I wonder if the length of filming somehow decreased. Possible reasons could be: content just needs the be produced quicker, or simply cost savings.

# Create column that counts number of days between two dates
summary %>% 
   mutate(
      n_days = difftime(filming_ended, filming_started, units = "days")
   ) %>% 
   pull(n_days)
## Time differences in days
##  [1] 38 41 38 38 38 38 38 38 38 38 38 38 38 38 38 38 38 38 38 38 38 38 38 38 38
## [26] 38 38 38 38 38 38 38 38 38 38 38 38 38 38 38

No its pretty much constant and always about 5 weeks.

Summary

As always: there is more to analyze, however, the purpose of this series is not to be exhaustive but to set a time limit and just examine as many questions as possible within the limit.

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