Briefle words · Data & charts
Indexed values
Also called index = 100
Dividing every value in a series by its starting value and multiplying by 100, so series with different units share one scale of relative change.
Say it to an AI
Line chart of monthly sessions and card spend, April to September, on one scale. Avoid a dual axis (secondary axis); instead plot indexed values (index = 100) rebased to April so the chart shows that sessions rose 40% while spend rose 8%, with a two-item colored key above the plot.
How an expert would brief the stronger version of “Sessions vs. spend chart”.
See it
Try it as a puzzle →Two-metric trend chart on the growth dashboard of a consumer fintech app.
Why: B's lines both start at 100 in April and end at 140 and 108 in September.
Related words
Room 3 · Axes & scales
Learn “Indexed values” in a five-minute lesson