Misleading Graphs Math Example 1
Follow the full solution, then compare it with the other examples linked below.
Example 1
easyA bar chart of company profits shows the y-axis starting at \950M. Profit Year 1: \960M, Year 2: \$970M. The bar for Year 2 appears to be twice as tall. Calculate the actual percentage increase and the visually implied increase.
Solution
- 1 Actual increase:
- 2 Visual impression: Year 2 bar is twice as tall as Year 1 (y-axis starts at 950, not 0) β implies 100% increase
- 3 Deception: the truncated y-axis exaggerates the 1% actual increase to look like 100%
- 4 Fix: start y-axis at 0, or clearly mark the axis break with a symbol (//) to indicate non-zero start
Answer
Actual increase: ~1%. Visual impression: ~100%. Truncated y-axis creates massive deception.
Truncating the y-axis is one of the most common forms of misleading graphs. Area below the bars represents zero baseline; cutting it off makes small differences appear enormous. Always check the y-axis origin before interpreting bar charts.
About Misleading Graphs
A misleading graph is a data visualization that distorts the true pattern through truncated axes, unequal intervals, cherry-picked data, or manipulated scales.
Learn more about Misleading Graphs βMore Misleading Graphs Examples
Example 2 medium
A graph shows 'cases of disease over time' with no y-axis label or values. The line goes up sharply.
Example 3 easyA 3D pie chart shows three categories: A=50%, B=30%, C=20%. The chart is tilted so C appears largest
Example 4 hardA graph shows 'gun deaths rise after Stand Your Ground laws.' The y-axis is inverted (high values at