Sociology / Soc 0182 · Procedure · 60–90 seconds
Reading a Misleading Chart
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Reading a chart critically means checking the axis, the baseline, the interval, and the scale before reading the shape, because each can be set to manufacture the impression.
Run five checks on any chart. First, the vertical axis: does it start at zero? An axis starting at 48 turns a move from 49 to 51 into a doubling by appearance. Second, the baseline year: a series beginning at an unusual peak or trough manufactures a decline or a rise that is only the return to normal. Third, the interval: uneven spacing on the horizontal axis — five years, then one, then ten — bends any line the author wants bent. Fourth, the scale: a bar chart using area or a picture that grows in two directions doubles the visual effect of a single doubling. Fifth, what is omitted: the years excluded, the categories merged into "other," the comparison group absent. None of these requires a false number. Every one of them is done with true data, which is why the chart survives fact-checking and still misleads.
A chart that fails these checks is not evidence of dishonesty — but it is not yet evidence of anything else either.