I'm Dreaming of a Colour Blind Christmas

Here are a few facts about yours truly

1. I'm not colour blind
2. I'm Canadian so I will continue to spell colour with a u (long live the queen)
3. I like to post data visualizations online
4. I try to choose colours that are obvious and don't require a legend.

These things combine for one sure thing about when I post content: I hit submit, leave my desk, and by the time I come back someone is, fairly, asking for a colour blind friendly version.
Roughly 10% of all men are colour blind, which somehow equates to about 50% of commentors on my public work. The colours most impacted by colour blindness are red and green, which can wreak havoc for any KPI analysis. To help see that havoc, here is a look at Christmas songs that have made the billboard top 100 since 1958

And here's what this looks like to a person who has protanopia color blindness (typically the most acute variety (shout-out to David for the translation))

​Not exactly festive. But most notably, take in how impossible it is to distinguish the red from the green. If this were a KPI chart, you'd get nowhere fast.
Alas, here are some tips for making a colour blind approachable dashboard.

1. Know your audience. CB friendliness is a must if you're posting to the masses of the internet. However if your scope is everyone from you to your VP and you know that colour blindness is not an issue, then go forth with a palette of your choosing.
2. Limit colours where possible. This is good advice for any data viz; colour should only be used to convey information that the chart doesn't inherently already put forth. Following this advice can already remove some hurdles.
3. If you want to work outside the confines of the grayscale, blue and orange are typically CB friendly. (And Blue can pass as a Christmas colour too!)
4. If you must use a red-green scale to convey KPIs, try a gray to green scale instead. The green won't come through, but the scale should still be intuitive enough to get the message across. It's also easier for colour blind people to distinguish light and dark shades rather than red vs green hues.

Here is the full colour version of the above dashboard, considering these tips (which I've included).

It's lost some festivity, sure, but it's also gotten to be a bit more palatable (sic.) to the 10% of men who we're having no fun earlier.