Working on interaction design experiments in Swift UI

Though the only real example of this — that I’ve seen — is the sleep tracking data in the iOS fitness app using a visual indicator to show when data is within my “normal” range. Apple also applied the same idea to non-time series data, to highlight the status of multiple variables at once.

In the 90’s, Donald Wheeler published a book about what he called a process behaviour chart, where a visual indicator communicates the range of expected values. It’s such a simple idea!

Though I’d call it the expected range chart.

This mistake is over-interpreting any high or low values as signal, when in reality those values often represent predictable variation.