Who is a millennial? An example of handling uncertainty

I found this fascinating chart from CNBC, which attempts to nail down the definition of a millennial.

It turns out everyone defines "millennials" differently. They found 23 different definitions. Some media outlets apply different definitions in different items.

I appreciate this effort a lot. The design is thoughtful. In making this chart, the designer added the following guides:

• The text draws attention to the definition with the shortest range of birth years, and the one with the largest range.
• The dashed gray gridlines help with reading the endpoints of each bar.
• The yellow band illustrates the so-called average range. It appears that this average range is formed by taking the average of the beginning years and the average of the ending years. This indicates a desire to allow comparisons between each definition and the average range.
• The bars are ordered by the ending birth year (right edge).

The underlying issue is how to display uncertainty. The interest here is not just to feature the "average" definition of a millennial but to show the range of definitions.

***

In making my chart, I apply a different way to find the "average" range. Given any year, say 1990, what is the chance that it is included in any of the definitions? In other words, what proportion of the definitions include that year? In the following chart, the darker the color, the more likely that year is included by the "average" opinion.

I ordered the bars from shortest to the longest so there is no need to annotate them. Based on this analysis, 90 percent (or higher) of the sources list 19651985 to 1993 as part of the range while 70 percent (or higher) list 19611981 to 1996 as part of the range.

 

 

Comments

[Derek Swingley]

Can you post a link to the accompanying CNBC story?

Also your chart says 1985 and 1981 but the post text says 1965 and 1961.

[Mahmood Shafeie Zargar]

1981 and 1985, you mean...

[Kaiser]

DS, MSZ: Thanks for the heads up. Fixed the text.

[Kaiser]

DS: I saved the chart some time ago. I think the article may have been this one.

[Howie]

I really like this chart revision. The original is pretty good but the revision is just super-easy and intuitive to read.

[Joost Romijn]

Awesome chart. Using a square for every year is better than just a bar and coloring them by uncertainty makes the overall conclusion a lot clearer in my opinion.