The plot below is from the Burge et al. 2020 Journal of Politics article "A Certain Type of Descriptive Representative? Understanding How the Skin Tone and Gender of Candidates Influences Black Politics":
I thought that the plot could be improved. Some superficial shortcomings of the plot:
[1] Placing dependent variable information in the legend unnecessary causes readers to need to decipher the dot, triangle, and X symbols.
[2] The y-axis text is unnecessarily vertical, and vertical text is more difficult to read than horizontal text.
[3] The panels are a lot taller than needed, so the top estimate is farther from the x-axis labels than needed.
Some other flaws are better understood with information about the experiment. Black participants were randomly assigned to groups and asked to rate a candidate, in which candidate characteristics varied, such as being female and dark skinned (Dark Julie) or male and light skinned (Light James). Participants responded to items about the candidate, such as reporting their willingness to vote for the candidate. The key result, indicated in the abstract, is that "darker-skinned candidates are evaluated more favorably than lighter-skinned candidates" (p. 1).
[4] The estimates of interest unnecessarily consume too little of the plot space. The dependent variables were placed on a 0-to-1 scale, and the plotted estimates are differences on this scale, so that -1 and +1 are potential estimates; the x-axes thus do not need to run from -0.5 to +0.5. The estimate of interest is the difference in responses between candidates and not the absolute values of the responses, so I think that it is fine to zoom in on the estimates and to not show the full potential scale on the x-axis.
Below is a plot that addresses these points:
I also changed the dependent variables from a 0-to-1 scale to a 0-to-100 scale, to avoid decimals in the x-axis, because decimals involve unnecessary periods and sometimes involve unnecessary zeros. For example, for the difference between Dark James and Light James in the middle panel, I would prefer to have the relevant tick labeled "5" than ".05" or "0.05".
And I removed what I thought was information that could be placed into a figure note or dropped altogether from the figure (such as sample size and model numbers). The note on the data source could also be placed into the figure note for journal publication, but I'm including it in this plot, in case I tweet the plot.
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Another potential improvement is to revise the plot to emphasize the key finding, about the skin tone difference. The original Burge et al. 2020 plot includes a comparison of Dark Julie to Dark James, but does not include a comparison of Light Julie to Light James (all three comparisons of Light Julie to Light James are nulls). But the inclusion of the third panel in the original Burge et al. 2020 plot dilutes the focus on the skin color comparison. Here is a plot focusing on only the dark/light comparison:
Potential shortcomings of the above plot are the absence of the absolute values for the estimates and an inability to make across-sex comparisons of, say, Light Julie to Dark James. The plot below includes absolute values, permits comparisons across sex, and still permits the key finding about skin color to be relatively easily discerned:
The plot below uses shading to encourage by-color comparison of candidate pairs within panel:
Maybe it would be better to emphasize the dark/light finding by using a light dot for the "Light" targets and a dark dot for the "Dark" candidates. And, for a stand-alone plot, maybe it would be better to add a title summarizing the key pattern, such as "Black participants tended to prefer the darker-skinned Black candidates". Feel free to comment on any other improvements that can be made.
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NOTES
1. Code and data for the 3-panel plot.
2. Code and data for the 2-panel plot.
3. Code and data for the unshaded 1-panel plot.
4. Code and data for the shaded 1-panel plot.
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