Effective tables

STAT1003 – Statistical Techniques

Dr. Emi Tanaka

Australian National University

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Table 1

“Table 1” is most commonly the first table in a scientific or medical research paper, providing a summary of the study population’s baseline characteristics (demographics, health metrics) stratified by group.


Adelie
(N=152)		 Chinstrap
(N=68)		 Gentoo
(N=124)		 Overall
(N=344)
Body mass (g)
Mean (SD) 3700 (459) 3730 (384) 5080 (504) 4200 (802)
Median [Min, Max] 3700 [2850, 4780] 3700 [2700, 4800] 5000 [3950, 6300] 4050 [2700, 6300]
Missing 1 (0.7%) 0 (0%) 1 (0.8%) 2 (0.6%)
Sex
Female 73 (48.0%) 34 (50.0%) 58 (46.8%) 165 (48.0%)
Male 73 (48.0%) 34 (50.0%) 61 (49.2%) 168 (48.8%)
Missing 6 (3.9%) 0 (0%) 5 (4.0%) 11 (3.2%)

What statistics to present?

  • What statistics to present depends on what you want to convey and your audience.

  • There are two key purposes of the table:

    1. display information; and
    2. communicate information.
  • In general, tables tend to be about display of information and graphs are preferred for communication.
  • However, if precision matters then tables can be better at communicating this than graphs.
  • Numerical summaries should convey the characteristics of the data, and the relationships between variables, that are relevant to the question at hand.

Contingency tables

Contingency table (also called cross-tabulation) is a type of table that displays the frequency distribution of variables, often used to explore the relationship between two or more categorical variables.

Island/Species Adelie Chinstrap Gentoo Total
Biscoe 12.8% (44) 0.0% (0) 36.0% (124) 48.8% (168)
Dream 16.3% (56) 19.8% (68) 0.0% (0) 36.0% (124)
Torgersen 15.1% (52) 0.0% (0) 0.0% (0) 15.1% (52)
Total 44.2% (152) 19.8% (68) 36.0% (124) 100.0% (344)

Numerical precision

Select an appropriate precision for your goal and audience.

Average Body Mass (g)
Species 5 d.p. 2 d.p. 0 d.p.
Adelie 3,700.66225 3700.66 3701
Gentoo 5,076.01626 5076.02 5076
Chinstrap 3,733.08824 3733.09 3733

Trailing zeroes

Display trailing zeroes to match selected precision of the column.

Trailing zeroes
Yes No
0.233 0.233
0.320 0.32
0.400 0.4
0.343 0.343

Measurement units

Change and display units as appropriate.

Average body mass
Species (g) (mg) (mg) (tonnes) (lbs)
Adelie 3700.662 3700662 3,700,662 3.70e-03 8.2
Gentoo 5076.016 5076016 5,076,016 5.08e-03 11.2
Chinstrap 3733.088 3733088 3,733,088 3.73e-03 8.2
  • Show comma every 3 digits (or other marks as needed).
    E.g. 1000000 is harder to read than 1,000,000.

Font and Column Alignment

To make it easier to read and compare values across rows:

  • use a fixed-width font (e.g. Courier New, Menlo)
  • Spanner labels are usually aligned in center
  • Right-align numbers
  • Left-align texts
Species
Body mass (lbs)
Left Center Right Left Center Right Variable-width Fixed-width
Adelie Adelie Adelie 8.159 8.159 8.159 8.159 8.159
Gentoo Gentoo Gentoo 11.191 11.191 11.191 11.191 11.191
Chinstrap Chinstrap Chinstrap 8.230 8.230 8.230 8.230 8.230

Labels within tables

  • It is possibly obvious, but tables designed as final product (e.g. in report) should have polished labels.
  • For columns, the unit may be written in the column header label.
  • You shouldn’t label the unit within the table.
✅
Species Average body mass (g) Average flipper length (mm)
Adelie 3700.7 190.0
Gentoo 5076.0 217.2
Chinstrap 3733.1 195.8
❌
Species Average body mass Average flipper length
Adelie 3700.7 g 190.0 mm
Gentoo 5076.0 g 217.2 mm
Chinstrap 3733.1 g 195.8 mm

Texts accompanying tables


Source: https://gt.rstudio.com/
  • Besides the contents of table, a table may be accompanied with: table header, caption, footnotes and/or source notes.
  • The conventions of how and what to write will depend on your audience and medium of report
  • Generally if you are communicating information, your caption should:
    • summarise the take-away message, in other words, why should the audience care about this table?
    • give context of the table (e.g. “\(R_0 > 1\) means that the virus is more infectious”)

🏗️ How to make tables in R?

  • There are many packages that make table in R, including ones that wrangle the data for you to make specialised table output. E.g. kableExtra, formattable, gt, DT, pander, modelsummary, gtsummary, gtExtras.

  • Some packages are designed to work with specific output formats (e.g. kableExtra works well with HTML and PDF output, but not with Word output). So you may want to choose a package that is compatible with your intended output format.

  • You can read the documentation for each packages to make the table you want.

  • Let us know in the dicussion forum if you have a favorite package for making tables!

When do you make tables over plots?

  • When you want to show exact values or the accuracy of the values are important to convey.

  • You can combine plots with tables!

Summary

  • Effective tables are designed to display and communicate information clearly and efficiently, using appropriate statistics, formatting, and accompanying texts to enhance understanding.
  • Ensure to use fixed-width fonts, right-align numbers, and left-align texts for better readability.
  • Use appropriate precision and units, and avoid redundant labels within the table.
  • When communicating information, include captions that summarise the key message and provide context for the table.
  • Consider using tables when exact values or precision are important, and combine with plots when appropriate to enhance communication.
  • There are many R packages available for creating tables, so choose one that suits your needs and intended output format.
  • Always consider your audience and the purpose of the table when designing it, to ensure it effectively conveys the intended information.