Reading Charts Honestly
How the same numbers can be drawn to tell opposite stories, through the axis, the scale, and the dates chosen, and what to check before trusting any chart of an investment.
The short version
A chart is a set of choices: where the vertical axis starts, whether equal distances mean equal dollars or equal percentages, which dates are included, and what exactly is being measured. Each choice can make the same numbers look calm or dramatic, good or bad. A 2.6% move can fill the whole frame. A century of steady growth can look like a flat line followed by an explosion. A ten-year record can show a loss or a tripling depending on the starting year. None of this requires false numbers. Read the axis and the dates before the line, and ask what the chart would look like drawn another way.
By the end of this lesson, you'll be able to
- Explain how the starting point of an axis changes the impression a chart gives
- Tell an ordinary scale from a log scale and say what each is good for
- Identify how the choice of dates and of what's measured can change the story a chart tells
Why this matters
Charts are everywhere in investing: in fund documents, in news stories, in apps, and in adverts. A chart is quicker to take in than a table, which is its strength and its risk. The impression arrives before you've read a single number, and whoever drew the chart decided what that impression would be. This lesson uses three charts you can switch between two or three views. In each one the numbers stay the same and only the drawing changes.
The rest of this lesson is for members
Still to come in this lesson: Where the axis starts, Ordinary scale and log scale, Where the chart starts and ends, What's being measured, Five checks, the key takeaways, and 2 quiz questions with explanations.
Membership opens every lesson in the curriculum, the capstone projects, the interactive tools, and the members-only channels in the Hyperion Entities Discord. The first lesson of every module stays free.
Go deeper
- Probability and Expected ValueMath and Statistics for Investors (depth track)
- Arithmetic and Geometric AveragesMath and Statistics for Investors (depth track)
- Bull Markets, Bear Markets, and RecoveriesPart 6: Strategy, Behavior, Accounts, and Taxes
- Inflation and Purchasing PowerPart 1: Foundations
Notes and sources
- Aswath Damodaran, NYU Stern School of Business. Historical Returns on Stocks, Bonds and Bills, with annual data through 2025 (updated January 2026). Checked 2026-10-12.