Forest Plot for Meta-Analysis Results — forest

Generates a forest plot from a meta-analysis result object, optionally grouped by a specified subgrouping variable.

Usage

forest_plot(
  mars_object,
  subgroups = NULL,
  z_dist = TRUE,
  xlab = "Effect Size",
  main = "Forest Plot",
  study_header = "Study",
  subgroup_header = "Group",
  es_header = "ES (SE)",
  note = NULL,
  ci_level = 0.95,
  marker_scale = 2,
  font_cex = 0.8,
  legend_position = "top",
  legend_title = NULL,
  legend_inset = c(0, -0.2),
  main_adj = 0.5,
  main_line = NULL
)

Arguments

mars_object: A fitted mars object.
subgroups: Optional. Name of the column in mars_object$data to use as subgroup variable.
z_dist: Logical. Whether to use the normal distribution for confidence intervals. If FALSE, uses the t-distribution.
xlab: Label for the x-axis. Defaults to "Effect Size".
main: Title of the forest plot. Defaults to "Forest Plot".
study_header: Label for the column showing study names. Defaults to "Study".
subgroup_header: Label for the subgroup column (if used). Defaults to "Group".
es_header: Label for the effect size column. Defaults to "ES (SE)".
note: Optional. Text or named list providing a summary note (e.g., effect, SE, tau², I²).
ci_level: Confidence level for the interval bounds. Defaults to 0.95.
marker_scale: Numeric multiplier for marker size. Defaults to 2.
font_cex: Numeric scaling for text labels. Defaults to 0.8.
legend_position: Legend position for subgroup labels. Use "none" to hide.
legend_title: Optional subgroup legend title.
legend_inset: Numeric inset passed to legend.
main_adj: Horizontal title alignment in [0, 1].
main_line: Optional title line. If NULL, default is used.

Value

A base R forest plot is rendered to the current graphics device.

Details

The function sorts studies by effect size and draws each study as a point with a confidence interval. If subgroups is provided, distinct plot symbols are used for each group and a legend is added. Optionally, a summary note can be added below the plot using the note argument.

Examples

if (FALSE) { # \dontrun{
forest_plot(mars_object,
            subgroups = "region",
            note = list(effect = 0.42, se = 0.05, tau2 = 0.02, I2 = 0.23))
} # }