MisleadingCharts
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The family doctor who shrank in two dimensions

Showing the misleading chart

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The LA Times drew the decline of California’s family doctors as a doctor pictogram scaled in height and width at once. The share fell to 44% of its 1964 level; the doctor kept about 20% of his ink. Tufte scored it a Lie Factor of 2.8.

01The claim

The California family doctor is vanishing before your eyes — by 1990 there will be barely a sliver left of the doctor there was in 1964.

02The trick

The numbers say the share of California doctors devoted solely to family practice fell from 27% in 1964 to a projected 12% by 1990 — to about 44% of where it started. The picture says something much worse, because the doctor shrinks in height and width together, and your eye reads ink, not edge lengths: scale both dimensions by 0.44 and the little doctor keeps only 0.44², about a fifth, of the original’s area. Tufte measured the printed version at a Lie Factor of 2.8 — the graphic shrinks nearly three times as fast as the data — and that was before counting the extra shrink from the overlaid perspective. A second, quieter trick rides along on the x-axis: 1964, 1975 and 1990 sit at equal spacing, squashing an 11-year gap and a 15-year gap into the same width — and that last, steepest-looking step is a projection dressed up as a measurement.

03The fix

Drawn as a plain line on a zero-based axis with the years where they actually fall, the same three numbers show a real but ordinary decline: 27%, then 16%, then a projected 12% — a fall of about half over 26 years, not a near-extinction. The pictogram isn’t the crime; the scaling is. If a figure must stand in for a value, scale its area to the value (or repeat identical icons, one per unit), keep time to scale, and draw projections so they look like guesses — an open marker and a dashed line, not another solid data point.