Somewhat related to an earlier post about whether or not Data.gov should integrate visualization is an article from The Economist back in 1998 about Deceptive Charts.
If a trade union were after a big pay rise, then the left-hand chart below would make a strong case. The facts seem obvious: the boss’s hourly pay has risen much faster than the workers’ pay. But plot exactly the same data on a logarithmic scale (see middle chart) and the story reverses; the wage gap now appears to narrow, with workers’ wages rising much faster than their boss’s. If the boss wants even stronger ammunition against the union’s pay claim, he might unveil the right-hand chart. This uses an index which sets both wages at 100 in the first year, and shows that his pay rises have lagged far behind his workers’. This corresponds to the facts, as all three charts were constructed on the (admittedly implausible) assumption that the boss’s pay had risen 5% and the workers’ pay 20% each year.
via Deceptive Charts.
