Figure types

2025-01-30

Rick Gilmore

Prelude

Channel (2024)

Overview

Announcements

Last time…

Making data

Core ideas

  • Data are made
    • Map characteristics (of people, things) to quantities/categories
      • By some measurement procedure
    • Reflect, but also select and deflect (Burke, 1968)
  • Mappings have different scale types (Stevens, 1946)
  • Scales determine i) permissible/logical stats & ii) best visualizations
flowchart LR
  Z[Researcher] -- Measures --> B[Thing/Person]
  B -- Makes --> C{Data}
  C --> D[Analyst]
  D -- Creates --> E(Figure)
  E -- Informs --> F[Student/Reader]
Figure 1: Illustration of mappings from observed entity to data figure

Data types/scales

  • Extending Stevens (1946), see also Wikipedia contributors (2024)
  • Nominal
    • Binary (0,1)
    • Categorical
  • Ordinal
    • e.g., 1st, 2nd, 3rd, …

Data types (continued)

  • Counts
    • e.g., 1, 2, 3, 4, …
  • Continuous/Real-valued
    • Interval
    • Ratio
  • Spatial data

What data type(s)?

https://psu-psychology.github.io/psych-490-data-viz-2025-spring/supplemental/psych-sci-figs.html#figure-1

What data type(s)?

https://psu-psychology.github.io/psych-490-data-viz-2025-spring/supplemental/psych-sci-figs.html#figure-3

What data type(s)?

https://psu-psychology.github.io/psych-490-data-viz-2025-spring/supplemental/psych-sci-figs.html#figure-26

What data type(s)?

https://psu-psychology.github.io/psych-490-data-viz-2025-spring/supplemental/other-field-figs.html#figure-15

What data type(s)?

https://psu-psychology.github.io/psych-490-data-viz-2025-spring/supplemental/other-field-figs.html#figure-21

Today

Goals

  • Practice making instruments for different data types
  • Understand how different data types map to
    • different types of data visualizations
    • different types of data summaries
  • Gain an appreciation of the variety of data visualizations

Mapping data types to figures

Considerations

  • What figure type(s) are appropriate for the data type
  • What figure type(s) are most informative/least misleading

Nominal data

  • Bar chart
  • Pie chart
  • Ring/donut chart
  • Mosaic chart (2 variables)

Ordinal data

  • All of the nominal types…
  • Sorted in some order based on the ordinal variable

Some examples

  • Using data created here

Bar chart

https://psu-psychology.github.io/psych-490-data-viz-2025-spring/tutorials/tutorial-making-data.html#visualizing

https://psu-psychology.github.io/psych-490-data-viz-2025-spring/tutorials/tutorial-making-data.html#horizontal-barplot

https://psu-psychology.github.io/psych-490-data-viz-2025-spring/tutorials/tutorial-making-data.html#lollipop-chart

https://psu-psychology.github.io/psych-490-data-viz-2025-spring/tutorials/tutorial-making-data.html#dodged-barplot

Bar, lollipop chart mappings

  • What data component maps to what figure dimension?
  • Number of observations in category \(\rightarrow\) height/length
  • Color-category \(\rightarrow\) fill color
  • School \(\rightarrow\) position on horizontal axis

Your turn

  • What aspects of these figures are helpful, informative?
  • What aspects are unhelpful, potentially confusing?
  • What are the advantages and disadvantages of having so many choices of figures?

Main points

Making figures

  • Multiple possible figure types for each data/scale type
  • Different data \(\rightarrow\) figure feature mappings
  • Figure types vary in clarity
    • Perceiving length/height vs. area

Next time

  • More figure types
    • Ordinal
    • Continuous
  • Components of data figures

Resources

References

Burke, K. (1968). Language as Symbolic Action. University of California Press. Retrieved from https://www.ucpress.edu/books/language-as-symbolic-action/paper
Channel, M. O. (2024). Every CHART types explained in 12 minutes. Youtube. Retrieved from https://www.youtube.com/watch?v=cuMwWvtNmJ0
Stevens, S. S. (1946). On the theory of scales of measurement. Science (New York, N.Y.), 103, 677–680. https://doi.org/10.1126/science.103.2684.677
Wikipedia contributors. (2024, November 23). Statistical data type. Retrieved from https://en.wikipedia.org/wiki/Statistical_data_type