Data Visualization: Turning Numbers Into Stories
Numbers hide stories. Charts reveal them.
Numbers hide stories. Charts reveal them.
Raw numbers are hard to understand. A table of 100 values is just noise. But plot those same numbers as a chart and patterns jump out instantly. Your brain processes images 60,000 times faster than text.
Click "Show Chart" to see the same data visualized.
John Snow stopped a cholera outbreak in 1854 by plotting cases on a map. The cluster around one water pump was obvious visually but invisible in the raw data.
Different data tells different stories. The same dataset can look clear or confusing depending on the chart type. Click each type to see the same data rendered differently.
Bar charts compare categories side by side.
Compare values across categories
Show change over time
Show parts of a whole
Show relationships between two variables
The same data can tell opposite stories depending on how you present it. Toggle between the honest and misleading versions to see common tricks.
The honest chart shows the full picture.
Starting the y-axis at 95 instead of 0 makes a 3% change look like a 60% change.
Showing only the months where sales dipped hides the overall upward trend.
3D pie charts distort proportions. Slices closer to the viewer appear larger than they are.
Test your new skills. Look at each chart and answer the question.
Edward Tufte, the "Picasso of data visualization," argues that the best charts have a high "data-ink ratio": every drop of ink should represent data, not decoration.
You can now look at a chart and understand what it is trying to say, spot when it is trying to trick you, and pick the right chart for any dataset.
Bar charts compare categories. Line charts show trends. Pie charts show parts of a whole. Picking wrong hides the insight.
Truncating the y-axis, using inconsistent scales, or cherry-picking time ranges can make tiny changes look dramatic.
A number means nothing alone. "500 users" could be great for a startup or terrible for Google. Always ask: compared to what?
The best visualizations make one point clearly. If you need a paragraph to explain your chart, simplify the chart.
Put your new knowledge into practice!