Four Checks Before You Trust a Graph

Lab Brief #8

🎯 Your mission

Learn the rule. Then catch nature using it.

⚡ The twist

Nature loves to surprise the careful watcher.

What you'll learn

Before reading any trend, check four things: whether the vertical axis starts at zero, what the units actually are, how the categories were chosen, and what period is shown. A truncated axis can make a 2% change look like a collapse. A start date chosen just after an unusual peak can reverse the apparent direction of a real underlying trend. None of these is a lie about the numbers — each is a true graph drawn to mislead.

Key words

truncated axis
An axis that does not start at zero, exaggerating the apparent size of a change.
cherry-picked period
A start and end date chosen so the trend shown differs from the trend in the full record.

Make a hypothesis first

Before you start: write down what you think will happen, and why.

Say your guess out loud — then find out if you were right.

Step 1 of 4 · Read

Think about what you just learned: say what "truncated axis" and "cherry-picked period" mean in your own words before you start.

Step 2 of 4 · Do

Take one honest dataset and draw it three times: with a zero axis, with a truncated axis, and over a cherry-picked five-year window. Write the headline each version would support and identify which numbers changed between them.

Step 3 of 4 · Observe

Record what actually happened, including anything that did not match what you expected.

Step 4 of 4 · Record

Write a conclusion that answers the question this lesson opened with, and state your uncertainty.

Question 1 of 3

A truncated vertical axis tends to make a small change look:

How sure are you?😐 maybe

Question 2 of 3

Choosing a start date just after an unusual peak can:

How sure are you?😐 maybe

Question 3 of 3

A misleading graph drawn from honest numbers shows that the problem lies in:

How sure are you?😐 maybe

Mind = blown

🔬 The more you look, the more nature shows you.

Nice work!

You got 0 of 3 right.

Next: Replication Is What Turns a Result into Knowledge All lessons

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✨ More to explore

🌍 Where you see this in real life: This shows up in your everyday life more than you'd think.

🏆 Stretch challenge (try it this week): Try one experiment in real life this week — even a tiny one.

👨‍👩‍👧 For the dinner table: “What's the most surprising thing you learned today?”

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