Create a bump chart. — bump

A bump chart shows how the rank of several entities changes across successive time periods. Each entity is drawn as a smooth line that moves up or down as it overtakes, or is overtaken by, the others, with a circle at every period showing its rank. Popularised by the Financial Times, The Economist and FiveThirtyEight (league tables, election polls, country rankings), it is the clearest way to tell a "who is ahead?" story when the order matters more than the exact values.

The data must be in long format: one row per entity and period. By default the ranks are computed per period from the numeric y column (rank 1 = highest value). Set ranked = TRUE if y already contains the ranks.

Usage

bump_chart(
  data,
  x,
  y,
  group,
  ranked = FALSE,
  rankOrder = "desc",
  colors = NULL,
  highlight = NULL,
  greyCol = "#d3d3d3",
  lineWidth = 3,
  circleRadius = 11,
  showRank = TRUE,
  title = NULL,
  titleFontSize = 16,
  xFontSize = 11,
  labelFontSize = 11,
  font = "Verdana, Geneva, Tahoma, sans-serif",
  bgcol = "white",
  axisCol = "black",
  width = NULL,
  height = NULL
)

Arguments

data: The data frame containing the variables to consider, in long format (one row per group and period).
x: The name of the column holding the time period. Numeric and Date columns are ordered chronologically, factors follow their level order and character columns follow their order of appearance.
y: The name of the numeric column holding the value to rank (or the rank itself when ranked = TRUE).
group: The name of the column identifying each entity (one line per entity). Each group can appear at most once per period.
ranked: Whether y already contains ranks. Defaults to FALSE, in which case ranks are computed per period from y.
rankOrder: How ranks are computed when ranked = FALSE. One of "desc" (default, the highest value gets rank 1) or "asc" (the lowest value gets rank 1). Ties are broken by order of appearance in the data.
colors: Optional. A character vector of colors, recycled across the groups in order of appearance, or a named vector mapping group names to colors. Colors must be valid CSS colors (e.g. "steelblue" or "#1f77b4"); R-only names such as "grey40" are not understood by the browser. Defaults to the D3 Tableau 10 palette.
highlight: Optional. A character vector of group names to highlight. All other groups are drawn in greyCol.
greyCol: Color used for groups that are not highlighted. Defaults to "#d3d3d3".
lineWidth: Width of the lines in pixels. Defaults to 3.
circleRadius: Maximum radius of the circles in pixels. It is reduced automatically when there are many groups or periods. Defaults to 11.
showRank: Whether to print the rank number inside each circle. Defaults to TRUE.
title: Optional. Title of the chart.
titleFontSize: Font size of the chart title. Defaults to 16.
xFontSize: Font size of the period labels on the x-axis. Defaults to 11.
labelFontSize: Font size of the group labels drawn at both ends of each line. Defaults to 11.
font: The font family used for all text. Defaults to "Verdana, Geneva, Tahoma, sans-serif".
bgcol: Background color of the SVG. Defaults to "white".
axisCol: Color of the period labels, grid lines and title. Defaults to "black".
width: Optional. The width of the SVG output.
height: Optional. The height of the SVG output.

Value

An SVG bump chart.

Examples

# Points scored by five teams over four seasons
league <- data.frame(
  season = rep(c("2023", "2024", "2025", "2026"), each = 5),
  team   = rep(c("Lions", "Tigers", "Bears", "Wolves", "Eagles"), 4),
  points = c(80, 75, 60, 55, 50,
             70, 82, 58, 66, 49,
             65, 78, 72, 69, 52,
             60, 74, 81, 70, 77)
)

bump_chart(
  data  = league,
  x     = "season",
  y     = "points",
  group = "team",
  title = "League ranking by season"
)


# GDP per capita rank of the Asian "tiger" economies, highlighting two
library(gapminder)

countries <- c("Japan", "Singapore", "Hong Kong, China", "Taiwan",
               "Korea, Rep.", "Malaysia", "Thailand", "China")
gdp <- gapminder[gapminder$country %in% countries &
                 gapminder$year >= 1967, ]
gdp$country <- as.character(gdp$country)

bump_chart(
  data      = gdp,
  x         = "year",
  y         = "gdpPercap",
  group     = "country",
  highlight = c("Singapore", "Korea, Rep."),
  title     = "GDP per capita rank, 1967-2007"
)