Percentage Point
Etymology
“Percent” is from Latin “per centum” (by the hundred); “point” marks the unit on a percentage scale. The compound was coined precisely to disambiguate a rise “from 4 percent to 6 percent,” which can be described two very different ways.
noun phrase · /per-SEN-tij POINT/
The arithmetic difference between two percentages, as opposed to the percentage change between them.
What it names
It fixes one of the most common and consequential number errors in journalism and politics.
Example
A rate going from 4 percent to 6 percent rose by two percentage points — but by 50 percent — and a headline that says either without the other can mislead.
Related idea
The trap is treating a percentage-point change as a percentage change; a 1-point drop in a 2 percent rate is a huge 50 percent cut, while a 1-point drop in a 90 percent rate is barely a ripple.
See also