How to read a chart without being fooled
Learn four moves to read any chart (what's measured, axes and baseline, scale, what to compare) and use them on a chart from a report.
Free course. Your Maestro, an AI, .
So far you've chosen charts to answer questions. But almost every chart you'll see in your life was made by someone else: a monthly report, a vendor's presentation, a news story, whatever a spreadsheet hands back to you. This module gives you a routine for reading any chart without letting your first impression win.
The first impression is fast and almost always goes with the shape: "sales collapsed", "this branch sells three times as much". Sometimes it's right. But the shape depends on decisions made by whoever built the chart, and those decisions are written around the edges: in the title, on the axes, in the small numbers. Reading well means reading the edges before the middle.
The four moves
They're four questions, always in this order. With practice they take a few seconds.
What's measured?
Read the title, the labels and the units. Pesos or tickets? The total or the average? For what period? What is each bar, dot or line: a branch, a month, a customer? If you can't answer this, there's nothing to read yet.
Axes and baseline
What's on each axis, and where does it start? In bars and areas, the axis for the amounts has to start at zero, because the length is the amount. In lines and dots it may not start at zero, but that changes how steep everything looks.
Scale
What steps do the axis marks go up in? Does each step add the same amount, or multiply? Are they pesos, thousands, millions or percentages? The same difference can be huge in pesos and small in percent, or the other way around.
What to compare?
What does the chart invite you to compare: neighboring bars, one line against another, one month against the one before? Is that the comparison that answers your question? Only now look at the shape and draw your conclusion.
Notice that the shape, the thing that jumps out at you, comes at the very end. Not because it doesn't matter, but because it only means something once you know what's measured and how it's drawn.
The four moves on a report chart
This chart comes from Centro's monthly report. Go through it with the four moves, one per step.
Step 1 of 5
Edges first
Before you look at the line, read the title and the axes. Don't conclude anything from the shape yet. The month labels are Spanish abbreviations (ene is January, dic is December). Synthetic data, CC0.
The conclusion after the four moves ("Centro's ticket goes up about 15 pesos in pan de muerto and rosca season") is more precise and more useful than the first impression ("it collapsed in February"). And you got there without any hard math: just by reading what the chart was already saying around its edges.
If you have to read a chart at work that you don't understand, describe it to your Maestro and go through the four moves together.
Now watch someone with experience apply the four moves to a chart you already know: the first one in the course, with the three branches. Open each step once you've thought through your own.
The four moves on the three-branch chart
Worked example · 4 steps
Remember the course's first chart: three bars with the 2025 sales of Providencia, Centro and Chapultepec, where Providencia's looks about five times taller than Chapultepec's. Read it with the four moves.
Work out the next step yourself, then open it to compare.
Check yourself: A report has a bar chart titled "Performance by branch", with no units on the axis. What's the first thing you can't know yet?
Try it
This chart comes from Tonalá's report. Read it with the four moves and write one sentence per move in the box below. Your Maestro goes over it with you.
Read Tonalá's ticket chart with the four moves. Write one sentence for each: what's measured, axes and baseline, scale, and what you would compare.
Check yourself: Read Tonalá's ticket chart with the four moves. Write one sentence for each: what's measured, axes and baseline, scale, and what you would compare.
Want to practice again? Ask your Maestro for a new chart to read with the four moves.