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Data and Society 9-12 / Week 08 / Mission Quest
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Week 08 · Charts That Mislead

Mission Quest

Mission Quest: Chart Check at Home
// How a true number can tell a false story
⏱ about 20 min

Mission Quest: Chart Check at Home

Comet arrives at the Commons with a folded flyer from a town garden club.

"It has a bar graph," she says. "Plot B grew four times as many plants as Plot A!"

Wren unfolds it and studies the axis. "What do you notice about where the y-axis starts?"

Comet squints, then grins. "It starts at 20. Same trick as my poster!"

Nova hovers above the flyer. "Would you like a hint?" she asks. "Charts are everywhere at home too. Check one with your family."

Wren nods. "Title, source, axis, steps. Let's make it a family game."

  1. A chart can use true numbers and still give a false picture.
  2. On a bar graph, the y-axis usually starts at 0 and is split into equal parts.
  3. Pie charts compare parts of a whole and do not show change over time.
  4. Every graph needs a title and a source line that gives credit.
  5. A claim needs the whole data, and often more than one source.
  6. Before sharing, ask who a chart could help and who it could harm.
◇ CHART CHECK AT HOME
With a family member, look for a printed chart at home: in a newspaper, magazine, flyer, book or school handout.
Use printed charts only. You do not need a screen or a website.
No printed chart at home? Use the made-up garden flyer in the table after this box, or one of Comet's posters from this week.
Check the chart together, one question at a time.
Does it have a title that says what it shows?
Does it have a source line that says where the data came from?
If it is a bar graph, where does the y-axis start, and are the steps equal?
Is it the right kind of chart for its job?
Does any claim printed beside it match the numbers?
Give the chart a score out of 5, one point for each yes.
Made-up garden flyerWhat it shows
TitlePlants grown this season
Source(none)
Plot A21 plants
Plot B24 plants
Y-axisStarts at 20, in equal steps of 1
Claim beside itPlot B grew four times as many plants!
For a grown-up
This week your student learned how charts can mislead even when the numbers are true.
Any printed chart works: a newspaper, a magazine, a flyer or a book. No screen is needed.
Ask: where does the y-axis start? Ask: does the claim match the numbers?
Everything in this course is done on paper. No app, website or account is needed.
QUEST CHECK (MADE-UP GARDEN FLYER)
  • Read the question.
  • Tap your answer.
With the y-axis starting at 20, how many steps tall is the Plot B bar?
Is the flyer's claim "four times as many plants" true?
What is missing from the flyer chart?

Fantastic work this week, data analyst. Next week you will find the typical value hiding in a column of numbers.

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