Stack Overflow Annual Developer Survey 2024

Demonstrating the round bias (preference for multiples of 5 or 10) by respondents in the Stack Overflow Annual Developer Survey 2024

Figure 1: Rounding bias, or digit preference bias, occurs when data is rounded to preferred digits, often leading to inaccurate results or skewed patterns. This is common in self-reported surveys where respondents favour certain numbers, such as rounding ages to multiples of 5 or 10. The above bar-chart shows a perfect example from the Stack Overflow Annual Developer Survey 2024 - response to the question - number of years spent coding.

How I made this graphic?

Loading libraries & data

# Data Import and Wrangling Tools
library(tidyverse)            # All things tidy

# Final plot tools
library(scales)               # Nice Scales for ggplot2
library(fontawesome)          # Icons display in ggplot2
library(ggtext)               # Markdown text support for ggplot2
library(showtext)             # Display fonts in ggplot2
library(colorspace)           # Lighten and Darken colours
library(seecolor)             # To print and view colours
library(patchwork)            # Combining plots

# Option 2: Read directly from GitHub
# qname_levels_single_response_crosswalk <- readr::read_csv('https://raw.githubusercontent.com/rfordatascience/tidytuesday/master/data/2024/2024-09-03/qname_levels_single_response_crosswalk.csv')
# stackoverflow_survey_questions <- readr::read_csv('https://raw.githubusercontent.com/rfordatascience/tidytuesday/master/data/2024/2024-09-03/stackoverflow_survey_questions.csv')
stackoverflow_survey_single_response <- readr::read_csv('https://raw.githubusercontent.com/rfordatascience/tidytuesday/master/data/2024/2024-09-03/stackoverflow_survey_single_response.csv')

Visualization Parameters

# Font for titles
font_add_google("Grenze Gotisch",
  family = "title_font"
) 

# Font for the caption
font_add_google("Barlow Condensed",
  family = "caption_font"
) 

# Font for plot text
font_add_google("Bellefair",
  family = "body_font"
) 

showtext_auto()

bg_col <- "grey95"
mypal <- c("grey40", "#D94801FF")

text_col <- "grey20"
text_hil <- text_col

bts <- 90

# Caption stuff for the plot
sysfonts::font_add(
  family = "Font Awesome 6 Brands",
  regular = here::here("docs", "Font Awesome 6 Brands-Regular-400.otf")
)
github <- "&#xf09b"
github_username <- "aditya-dahiya"
xtwitter <- "&#xe61b"
xtwitter_username <- "@adityadahiyaias"
social_caption_1 <- glue::glue("<span style='font-family:\"Font Awesome 6 Brands\";'>{github};</span> <span style='color: {text_hil}'>{github_username}  </span>")
social_caption_2 <- glue::glue("<span style='font-family:\"Font Awesome 6 Brands\";'>{xtwitter};</span> <span style='color: {text_hil}'>{xtwitter_username}</span>")

plot_title <- "Rounding Bias"

plot_subtitle <- glue::glue("The Stack Overflow Annual Developer<br>Survey 2024 surveyed over 64,000<br>developers, and shows a good example of<br>Rouding Bias (or digit preference bias)<br>where respondents tend to round off<br>their answers to<b style='color:{mypal[2]}'> multiples of 5 or 10</b><br>for the number of years they<br>have spent coding.")

plot_subtitle |> str_view()

plot_caption <- paste0(
  "**Data:** Havisha Khurana & Stack Overflow", 
  " |  **Code:** ", 
  social_caption_1, 
  " |  **Graphics:** ", 
  social_caption_2
  )

rm(github, github_username, xtwitter, 
   xtwitter_username, social_caption_1, 
   social_caption_2)

The static plot

g <- stackoverflow_survey_single_response |> 
  select(years_code) |> 
  filter(years_code <= 50) |> 
  mutate(
    colour_var = ((years_code %% 5) == 0)
  ) |> 
  ggplot(
    mapping = aes(
      years_code
    )
  ) +
  geom_bar(
    mapping = aes(
      years_code,
      fill = colour_var
    )
  ) +
  geom_text(
    data = tibble(years_code = 0:50),
    mapping = aes(
      y = -10,
      x = years_code,
      label = years_code,
      colour = ((years_code %% 5) == 0)
    ),
    vjust = 1,
    size = bts / 6
  ) +
  annotate(
    geom = "richtext",
    x = 50,
    y = 4100,
    label = plot_subtitle,
    hjust = 1,
    vjust = 1,
    lineheight = 0.3,
    colour = text_col,
    family = "body_font",
    size = bts / 2,
    label.size = NA
  ) +
  scale_colour_manual(values = mypal) +
  scale_fill_manual(values = mypal) +
  scale_x_continuous(
    expand = expansion(0.02)
  ) +
  scale_y_continuous(
    expand = expansion(c(0.02, 0)),
    labels = label_number()
  ) +
  coord_cartesian(clip = "off") +
  labs(
    title = plot_title,
    # subtitle = plot_subtitle,
    caption = plot_caption,
    y = "Number of respondents",
    x = "Years spent coding by the respondents"
  ) +
  theme_classic(
    base_family = "body_font",
    base_size = bts
  ) +
  theme(
    text = element_text(
      colour = text_col,
      lineheight = 0.3
    ),
    
    # Legend
    legend.position = "none",
    
    # Axes & Other Stuff
    panel.grid = element_blank(),
    plot.margin = margin(15,5,5,5, "mm"),
    axis.line = element_line(
      colour = "grey30",
      arrow = arrow(length = unit(5, "mm")),
      linewidth = 0.5
    ),
    axis.title = element_text(
      margin = margin(0,0,0,0, "mm")
    ),
    axis.text = element_text(
      margin = margin(0,0,0,0, "mm"),
      colour = text_col
    ),
    axis.ticks = element_blank(),
    axis.ticks.length = unit(0, "mm"),
    
    
    # Labels
    plot.title.position = "plot",
    plot.title = element_text(
      family = "title_font",
      margin = margin(0,0,0,0, "mm"),
      size = 5 * bts,
      hjust = 0.5,
      colour = mypal[2]
    ),
    plot.subtitle = element_text(
      margin = margin(0,0,0,0, "mm"), 
      hjust = 0.5
    ),
    plot.caption = element_textbox(
      margin = margin(10,0,0,0, "mm"),
      hjust = 0.5,
      family = "caption_font"
    )
  )

ggsave(
  filename = here::here("data_vizs", "tidy_stack_overflow.png"),
  plot = g,
  width = 400,    # Best Twitter Aspect Ratio = 5:4
  height = 500,   
  units = "mm",
  bg = "white"
)

Savings the graphics

library(magick)
# Saving a thumbnail for the webpage
image_read(here::here("data_vizs", "tidy_stack_overflow.png")) |> 
  image_resize(geometry = "400") |> 
  image_write(
    here::here(
      "data_vizs", 
      "thumbnails", 
      "tidy_stack_overflow.png"
    )
  )