When You Cut the Y-Axis
by Anonymous · ⭐ 1 · 🍴 0
🔪 Four groups collected 48, 50, 52, and 54 stickers—almost the same, right? But if the vertical axis starts at 47, first place can look «7 times» last place! The numbers haven’t changed at all. Change the axis starting value and see for yourself how the big number in the middle can puff up from 1.1× to 7×. ✂️ Next, cut the time period. There was hardly any change over twelve months, but showing only March to June makes a graph that «shoots up». Show only June to September, and it «drops sharply» instead. Same data! The small graph below shows where you are in the whole picture. 🎯 Last, spot the trick: Which of the four graphs is honest? This app was made with code too · Remix it with data from your class!
About this app
An interactive data-literacy activity that demonstrates how chart design can change the story without changing the underlying numbers. Explore how starting the y-axis above zero exaggerates small differences between teams, how selecting only part of a 12-month period can make data appear to rise or fall, and how to identify misleading charts.
Use cases
- Teachers introducing graph literacy to elementary students
- Students learning to question chart scales and time ranges
- Classroom discussions about misleading data visualizations
- Families practicing critical thinking with simple charts
Features
- Adjustable y-axis starting values with comparisons of apparent and actual ratios
- Interactive 12-month period selection using start and end months
- Mini overview chart showing the selected period within the full year
- Quiz identifying truncated axes, cropped periods, honest charts, or both tricks
- Reset and next controls across three learning tabs
- Optional sound toggle