Create a Hierarchical Tree Diagram

Draws a left-to-right node-link tree from a set of columns given in order. The first column forms the top-level branches, the next column their children, and so on; multi-value cells are split so a study can sit in several branches. Each level-1 branch gets its own colour, inherited by its descendants, and the leaves can attach a wrapped list of the studies that reach them. Returns a standard ggplot2::ggplot object.

Usage

reviewTree(
  data,
  cols,
  study_id = StudyID,
  sep = "\r\n",
  show_members = TRUE,
  member_wrap = 36,
  label_wrap = 18,
  counts = c("none", "count", "percent", "both"),
  root_label = "All studies",
  colors = PALETTE,
  root_fill = "#F4F4C8",
  base_size = 11,
  na.rm = TRUE,
  na_label = "Not reported",
  na_last = FALSE
)

Arguments

data

A data frame with one row per study.

cols

Character vector of columns defining the hierarchy, from root (first) to leaf (last). Each level branches by that column's values.

study_id

Column with the study labels collected at the leaves (quoted or unquoted). Defaults to StudyID.

sep

Character. Separator for multi-value cells. Defaults to "\r\n".

show_members

Logical. Attach a box listing the contributing studies at each leaf. Defaults to TRUE.

member_wrap

Integer. Wrap the member list at this many characters. Defaults to 36.

label_wrap

Integer. Wrap node labels at this many characters. Defaults to 18.

counts

Character. Annotate each node with the number and/or percentage of studies it covers: "none" (default), "count", "percent", or "both". Counts are distinct studies; percentages are relative to all studies, so sibling branches may sum past 100% when cells are multi-valued.

root_label

Character. Text for the root node. Defaults to "All studies".

colors

Character vector of branch colours (one per level-1 value). Defaults to PALETTE.

root_fill

Character. Fill for the root node. Defaults to "#F4F4C8".

base_size

Numeric. Base font size in points. Defaults to 11.

na.rm

Logical. Drop missing values? Defaults to TRUE.

na_label

Character. Label for missing values when na.rm = FALSE. Defaults to "Not reported".

na_last

Logical. If TRUE (and na.rm = FALSE), order the missing branch last (at the bottom) at every level. Defaults to FALSE.

Value

A ggplot2::ggplot object.

Examples

data(studies)
reviewTree(studies, c("InterventionType", "Intervention"), study_id = Author)