Apr 24 2024
When Not to Connect the Dots
When plotting a sequence of points, should we connect the dots into a line? We usually do, but it shouldn’t be a foregone conclusion. Every chart element should have a clear and precise meaning: if we can’t explain what it means or it is ambiguous, it confuses readers and we should omit it.
The bulk of the SPC literature shows Control Charts as broken-line graphs. 100 years ago, Walter Shewhart, the inventor of these charts, plotted separate points instead. He did not explain why, so it’s on us to try and figure out what may have been his reasons.
Jul 21 2024
Rankings and Bump Charts
Hectar’s Audrey Bourolleau and Francis Nappez presented their findings about greenhouse gas emissions in the industrial production of bread baguettes at the 2024 Lean Summit in France. They see a major impact in (1) farming and (2) the production of fertilizer and plant protection products. Together, these categories account for 58% of total emissions but barely 6% of the costs. This suggests that improvements in these two areas could cut emissions in half with a minimal impact on bread prices.
This is about the visualization of this kind of information with bump charts/slopegraphs. Edward Tufte prefers slopegraph but bump chart is more common.
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By Michel Baudin • Data science • 0 • Tags: Bump chart, Slopegraph, Visualization