gt Skill

R table formatting ecosystem for publication-quality tables. Covers gt 1.3.0 for grammar-of-tables construction (gt(), fmt_() number formatting, tab_() structure, cols_*() column operations, gtsave() export), kableExtra 1.4.0 for knitr/kable HTML and LaTeX table styling in Quarto documents, and modelsummary 2.6.0 for formatting regression output from lm/glm/fixest/plm models into publication tables. Use when execution language is R and the task involves creating formatted data tables, summary tables, or regression tables for reports or papers. Python counterpart: the great-tables skill (same author, same grammar of tables) — use it when execution language is Python. For visualization (charts/plots), use ggplot2 instead. For document structure and rendering, use quarto instead.

What is gt?

gt implements a grammar of tables for R, analogous to ggplot2's grammar of graphics but for tabular output:

• Declarative: Build tables by layering formatting, structure, and style
• Pipeline-friendly: Chain operations with |> (data frame in, gt table out)
• Rich formatting: Number formatting (fmt_number, fmt_percent, fmt_currency), conditional styling, color scales, icons, images in cells
• Structured: Table header, column spanners, row groups, summary rows, footnotes, source notes
• Export: HTML, PNG, LaTeX, Word, RTF via gtsave()

kableExtra extends knitr's kable() for HTML and LaTeX table styling:

• Lightweight alternative when gt is overkill (simple summary tables in Quarto)
• Row/column styling, striped rows, scroll boxes, grouped rows
• Tight integration with Quarto's knitr engine

modelsummary formats regression output into publication-ready tables:

• Supports 100+ model classes (lm, glm, fixest, plm, survey, etc.)
• Side-by-side model comparison with custom coefficient labels
• Output to gt, kableExtra, HTML, LaTeX, Word, markdown, PNG
• Robust/clustered SEs via vcov argument (no re-fitting needed)
• Already covered in depth by the r-stats skill (reporting.md) and referenced by fixest -- this skill provides the table-formatting perspective

Version Notes

• gt 1.3.0: Stable release. Full grammar-of-tables API. fmt_*() family for number formatting, tab_*() for structural elements, cols_*() for column operations, opt_*() for table options.
• kableExtra 1.4.0: Stable release. kbl() replaces knitr::kable() as the recommended entry point. Full HTML and LaTeX styling support.
• modelsummary 2.6.0: Supports gt and kableExtra as output backends. The default output backend in modelsummary 2.x is tinytable — request a gt object explicitly with output = "gt". See r-stats skill reporting.md for comprehensive modelsummary coverage.
• knitr 1.51: Provides the underlying kable() function that kableExtra extends.

How to Use This Skill

Reference File Structure

File	Purpose	When to Read
quickstart.md	Basic gt() table, headers/footers/source notes, simple formatting	Starting out or need a quick table
formatting.md	fmt_*() family, conditional styling, spanners, row groups, summary rows	Detailed formatting and structure
modelsummary-tables.md	Regression tables via modelsummary(), customization, multi-model comparison	Formatting regression output
export.md	gtsave(), kableExtra in Quarto, inline tables in .qmd, output formats	Saving or embedding tables

Reading Order

1. Quick data table? Start with quickstart.md
2. Complex formatting? Read formatting.md
3. Regression table? Read modelsummary-tables.md
4. Saving or embedding? Read export.md
5. Simple Quarto table? Read export.md (kableExtra section)

Related Skills

Skill	Relationship
ggplot2	Visualization (charts/plots) -- use ggplot2 for figures, gt for tables
quarto	Document rendering -- gt/kableExtra tables render in .qmd documents
fixest	Regression output -- fixest models feed into modelsummary/gt tables. fixest's own etable() is an alternative to modelsummary for fixest-only output
r-stats	Regression output -- lm/glm models feed into modelsummary/gt tables. r-stats reporting.md has comprehensive modelsummary coverage
plm	Panel model output -- plm models feed into modelsummary/gt tables
data-scientist	Methodology guidance for what to present in tables

Python counterpart: Use the great-tables skill for Python table formatting. The great-tables package (version 0.21.0, by the same author as gt, implementing the same grammar of tables) is DAAF's Python table-formatting tool — load that skill when execution language is Python. Note surface differences from gt: method chaining instead of |>, 0-based cols_merge pattern indices, Polars expressions in grand_summary_rows, and HTML/LaTeX export in-process (but no working PNG export in the container). For regression tables in Python, great-tables has no modelsummary equivalent — use pyfixest's etable() or statsmodels' summary().

Quick Decision Trees

"I need to make a table"

What kind of table?
+-- Data summary table (descriptive stats, crosstabs)
|   +-- Simple (few rows/columns, minimal formatting)
|   |   +-- In a Quarto doc? --> kableExtra kbl() in ./references/export.md
|   |   +-- Standalone? --> gt() in ./references/quickstart.md
|   +-- Complex (conditional formatting, row groups, summary rows)
|       +-- gt() in ./references/formatting.md
+-- Regression table (model coefficients)
|   +-- Single model --> ./references/modelsummary-tables.md
|   +-- Multiple models side-by-side --> ./references/modelsummary-tables.md
|   +-- fixest models only --> Consider fixest etable() (see fixest skill)
|       OR modelsummary() for more customization
+-- Frequency / cross-tabulation table
|   +-- gt() with row groups --> ./references/formatting.md
+-- Table with color scales or conditional formatting
    +-- gt tab_style() or data_color() --> ./references/formatting.md

"Which package should I use?"

Choosing a table package?
+-- Publication-quality data table with rich formatting
|   +-- gt() (most flexible, best output quality)
+-- Regression table (multiple models, SEs, goodness-of-fit)
|   +-- modelsummary() (purpose-built for this)
+-- Simple table in a Quarto document
|   +-- kableExtra kbl() (lightweight, integrates with knitr)
+-- Quick console output (not for publication)
|   +-- print() or knitr::kable() (no extra packages needed)
+-- LaTeX table for a journal submission
    +-- gt() with gtsave("file.tex") OR modelsummary(output = "latex")

File-First Execution in Research Workflows

In DAAF research pipelines, tables are generated through script files in scripts/stage8_analysis/, not interactively. This ensures auditability and reproducibility.

The pattern:

1. Write table code to scripts/stage8_analysis/{step}_{table-name}.R
2. Execute via bash {BASE_DIR}/scripts/run_with_capture.sh {script_path}
3. Output gets appended to the script as comments
4. Use gtsave() to save tables to the project output directory

See agent_reference/SCRIPT_EXECUTION_REFERENCE.md for the mandatory file-first execution protocol.

Quick Reference

Essential Setup

library(gt)
library(kableExtra)
library(modelsummary)

Basic gt Table

tbl <- df |>
  gt() |>
  tab_header(
    title = "Table Title",
    subtitle = "Subtitle or description"
  ) |>
  tab_source_note("Source: Dataset name, year.") |>
  fmt_number(columns = where(is.numeric), decimals = 2)

Core gt Operations

Operation	Code
Create table	gt(df) or `df
Title/subtitle	tab_header(title, subtitle)
Source note	tab_source_note("Source: ...")
Footnote	tab_footnote(footnote, locations)
Format numbers	fmt_number(columns, decimals)
Format percent	fmt_percent(columns, decimals)
Format currency	fmt_currency(columns, currency)
Format date	fmt_date(columns, date_style)
Column spanner	tab_spanner(label, columns)
Row group	gt(groupname_col = "group_var")
Summary row	summary_rows(groups, fns, columns)
Conditional style	tab_style(style, locations)
Column labels	cols_label(col1 = "Label 1")
Hide columns	cols_hide(columns)
Column width	cols_width(col1 ~ px(150))
Save	gtsave(tbl, "file.html")

kableExtra Quick Pattern

df |>
  kbl(format = "html", digits = 2, caption = "Table Title") |>
  kable_styling(bootstrap_options = c("striped", "hover", "condensed")) |>
  add_header_above(c(" " = 1, "Group A" = 2, "Group B" = 2))

modelsummary Quick Pattern

modelsummary(
  list("Model 1" = fit1, "Model 2" = fit2),
  stars = c("*" = 0.05, "**" = 0.01, "***" = 0.001),
  coef_rename = c("x1" = "Education", "x2" = "Experience"),
  gof_map = c("nobs", "r.squared", "adj.r.squared"),
  output = "gt"
)

Topic Index

Topic	Reference File
Basic gt table creation	./references/quickstart.md
tab_header, tab_source_note	./references/quickstart.md
tab_footnote	./references/quickstart.md
Simple number formatting	./references/quickstart.md
cols_label column renaming	./references/quickstart.md
fmt_number, fmt_percent, fmt_currency	./references/formatting.md
fmt_date, fmt_integer	./references/formatting.md
Conditional formatting (tab_style)	./references/formatting.md
Color scales (data_color)	./references/formatting.md
Column spanners (tab_spanner)	./references/formatting.md
Row groups	./references/formatting.md
Summary rows	./references/formatting.md
Grand summary	./references/formatting.md
Column width and alignment	./references/formatting.md
Merge cells	./references/formatting.md
modelsummary basic usage	./references/modelsummary-tables.md
Multi-model comparison	./references/modelsummary-tables.md
Coefficient renaming and omission	./references/modelsummary-tables.md
Custom statistics rows	./references/modelsummary-tables.md
Robust/clustered SEs in tables	./references/modelsummary-tables.md
fixest models in modelsummary	./references/modelsummary-tables.md
Stars and significance formatting	./references/modelsummary-tables.md
gtsave to HTML/PNG/LaTeX	./references/export.md
kableExtra in Quarto	./references/export.md
Inline tables in .qmd	./references/export.md
Output format comparison	./references/export.md

Citation

When gt is used as a primary table-formatting tool, include in the report's Software & Tools references:

Iannone, R., Cheng, J., Schloerke, B., Hughes, E., Lauer, A., & Seo, J. (2024). gt: Easily Create Presentation-Ready Display Tables. R package version 1.3.0. https://gt.rstudio.com/

Cite when: gt produces tables included in the report or deliverables. Do not cite when: Only used for quick exploratory tables not included in deliverables.

For modelsummary citation (when used for regression tables):

Arel-Bundock, V. (2022). "modelsummary: Data and Model Summaries in R." Journal of Statistical Software, 103(1), 1-23.

For kableExtra citation (when used for Quarto table styling):

Zhu, H. (2024). kableExtra: Construct Complex Table with kable and Pipe Syntax. R package version 1.4.0.