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Data in the MMWR

Figures (8 of 12)

Data in the MMWR (§5.7): Figures
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2026-02-03

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Posted to LinkedIn on 2026-02-03. The text below is the post as published.

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Data in the MMWR (§5.7): Figures On this site (opens in a new tab)
[2026-02-03]

Principles: Figures follow modern visualization practices for statistical graphics, which include “Maximize the data-ink ratio” and “Forgo chartjunk.” Bar charts, dot plots, and other graphic elements, with or without error bars, are used based on empirical research regarding their effectiveness. As with other figure elements, data and analytic concepts are described with enough detail that the figure can stand apart from its report. In particular, analytic and inferential procedures are correctly named, often in a figure’s footnote.

Observations: The following issues in figures in the reviewed reports: Dual-scale axes, meaning that the scale on one side differs from the scale on the other. Broken axes, meaning that an axis has a visible gap meant to replace an even larger gap, as a way of reducing the total extent if the axis were unbroken. Bar charts with superposed intervals, also known as dynamite charts. Issues of scale, including the extent of the axis relative to the extent of depicted data, the overall use of space, and the use of transformations like the logarithm. Use of visual reference features that do not directly depict data elements, including frames around graphic panels, grids, and other guides. Scatterplot smooths. Multiple intervals, either around dots or around points on a line graph. Partial information on estimation or inferential procedures.

Recommendations: Maximize the data-ink ratio and forgo chartjunk. Deemphasize nondata elements, such as grids. Render panels with 1 or 2 axes rather than 4-sided frames. Allow direct labeling of graphic components as an alternative to a legend. Adapt the vertical and horizontal extents of a graphic to the scale of the data to make better use of available space and reader focus. Favor dot plots over bar charts; reserve bar charts for nonnegative counts or proportions. Always name inferential procedures to say how P-values and CIs were obtained. A graphic should almost never contain components on multiple scales. If a graphic is presented with multiple scales, then the relationship between those scales should be carefully planned to avoid distorting data or relationships between data elements.  When graphics contain multiple panels, ensure that a reader can relate the scales between components. For example, apply the same horizontal and vertical extents to each component, unless doing so obscures visual elements. Assure that graphics render well in grayscale.

Next topic: Interpret effects and their significance (§6.1)

Data in the MMWR