Truncating the Y-Axis: Threat or Menace?

Michael Correll, Enrico Bertini, Steven Franconeri

    Research output: Chapter in Book/Report/Conference proceedingConference contribution


    Bar charts with y-axes that don't begin at zero can visually exaggerate effect sizes. However, advice for whether or not to truncate the y-axis can be equivocal for other visualization types. In this paper we present examples of visualizations where this y-axis truncation can be beneficial as well as harmful, depending on the communicative and analytic intent. We also present the results of a series of crowd-sourced experiments in which we examine how y-axis truncation impacts subjective effect size across visualization types, and we explore alternative designs that more directly alert viewers to this truncation. We find that the subjective impact of axis truncation is persistent across visualizations designs, even for designs with explicit visual cues that indicate truncation has taken place. We suggest that designers consider the scale of the meaningful effect sizes and variation they intend to communicate, regardless of the visual encoding.

    Original languageEnglish (US)
    Title of host publicationCHI 2020 - Proceedings of the 2020 CHI Conference on Human Factors in Computing Systems
    PublisherAssociation for Computing Machinery
    ISBN (Electronic)9781450367080
    StatePublished - Apr 21 2020
    Event2020 ACM CHI Conference on Human Factors in Computing Systems, CHI 2020 - Honolulu, United States
    Duration: Apr 25 2020Apr 30 2020

    Publication series

    NameConference on Human Factors in Computing Systems - Proceedings


    Conference2020 ACM CHI Conference on Human Factors in Computing Systems, CHI 2020
    Country/TerritoryUnited States


    • deceptive visualization
    • information visualization

    ASJC Scopus subject areas

    • Computer Graphics and Computer-Aided Design
    • Human-Computer Interaction
    • Software


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