The field guide
15 ways a chart can lie
Learn these and you can walk through the gallery unsupervised. Each technique page explains the trick, how to spot it in the wild, and what the honest version looks like.
Axis crimes
Where most chart lies begin: the humble axis, bent until the data confesses.
The truncated axis
A 3% difference, presented as a landslide.
Bar charts encode value as length, so the baseline has to be zero — chop the bottom off the axis and a bar twice as tall no longer means twice as much. Start the axis at 94 and a one-point gap reads as total domination.
1 exhibit in the gallery
Dual y-axes
Two axes, one narrative, infinite flexibility.
Put one series on the left axis and another on the right, and you get two free knobs to turn until the lines cross exactly where the story needs them to. The correlation you “see” is a design decision, not a finding.
1 exhibit in the gallery
The inverted axis
Up is down. Less is more.
Flip the y-axis so larger values plot lower, and every trend reads backwards. Famously used to make a rise in gun deaths look like a decline — at a glance the chart says the exact opposite of its own numbers.
No exhibits yet — the wall awaits
Uneven intervals
1990, 1995, 2000, 2004, 2006, 2007 — evenly spaced.
Plot irregular time steps at regular spacing and you silently stretch some periods and compress others. Slopes become fiction: a decade and a single year occupy the same width, so the “acceleration” is typography.
No exhibits yet — the wall awaits
Size & scale
When 2× somehow looks like 8×. Your eye reads ink, not numbers.
The area illusion
Twice the value, four times the ink.
Scale an icon’s or circle’s height by the data and its area grows by the square. A value that doubled looks quadrupled — and in 3D, octupled. Your eye judges the ink, not the radius.
No exhibits yet — the wall awaits
Gratuitous 3D
The slice in front always wins.
Tilt a pie chart into 3D and perspective inflates whatever sits closest to the viewer, with a thick rim thrown in as bonus ink. 3D bars pull the same trick with parallax — nobody can tell where the tops actually are.
No exhibits yet — the wall awaits
The impossible pie
70% + 63% + 60% = one pie chart.
A pie chart promises that its slices sum to a whole. Feed it multi-select survey data — where respondents could pick several answers — and you get confident-looking slices adding up to 193%.
No exhibits yet — the wall awaits
Cherry-picking
The data shown is real. The data missing is the story.
The cherry-picked window
The trend depends on when you press start.
Zoom to the right five years and almost any series can be made to soar, crash, or flatline. The data is untouched — the crop does all the work.
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The convenient comparison
We’re #1 — among the competitors we chose.
Any bar looks tall next to the right neighbors. Pick the comparison set after seeing the numbers and “leading the industry” becomes a certainty rather than an achievement.
No exhibits yet — the wall awaits
Survivorship bias
Plotting only the planes that made it home.
If the dataset only contains winners — funds that still exist, companies that went public, planes that returned — every trend tilts rosy. The bullet holes you can see are the ones that didn’t matter.
No exhibits yet — the wall awaits
The ever-rising cumulative
A metric that literally cannot go down.
Plot “cumulative units sold” and the line rises forever, even while the underlying sales collapse. It is the chart equivalent of only counting up.
1 exhibit in the gallery
Framing & context
Technically true, practically misleading.
The missing denominator
More of everything happens in California. More people live there.
Raw counts mostly measure population. Big places top every list — sales, crimes, disease — until you divide by the thing the question is actually about.
No exhibits yet — the wall awaits
Spurious correlation
Margarine consumption and the divorce rate in Maine: a love story.
Comb through enough series and some will move together beautifully by pure chance — or because both quietly follow population, inflation, or time itself. A tight fit on a chart is not a mechanism.
1 exhibit in the gallery
Strategic binning
The map whose color breaks were drawn after the data arrived.
A choropleth’s story lives in its color breaks. Set the bins at 0–10, 10–12, and 12–90 and you can paint the country any shade of crisis you like. Continuous data, discrete lies.
No exhibits yet — the wall awaits
Phantom precision
n = 6, error bars sold separately.
A crisp bar chart looks exactly as confident whether it rests on six million data points or six. Drop the error bars and noise dresses up as signal.
No exhibits yet — the wall awaits