Yesterday, I posted the following chart in the post about Cornell's Covid-19 case rate after re-opening for in-person instruction.
This is an edited version of the chart used in Peter Frazier's presentation.
The original chart carries with it the burden of Excel defaults.
What did I change and why?
I switched away from the default color scheme, which ignores the relationships between the two lines. In particular, the key comparison on this chart should be the actual case rate versus the nominal case rate. In addition, the three lines at the top are related as they all come from the same underlying mathematical model. I used the same color but different shades.
Also, instead of placing the legend as far away from the data labels as possible, I moved the line labels next to the data labels.
Instead of daily date labels, I moved to weekly labels, and set the month names on a separate level than the day names.
The dots were removed from the top three lines but I'd have retained them, perhaps with some level of transparency, if I spent more time making the edits. I'd definitely keep the last dot to make it clear that the blue lines contain one extra dot.
Every graphing program has defaults, typically computed by some algorithm tuned to the average chart. Don't settle for the average chart. Get rid of any default setting that slows down understanding.