Percentages: generating confusion
Calculating percentages and handling them confuse a lot of people generating content.
Yet, we can all do it, with a little patience and practice. A high point of training people to read accounts is when the penny of percentages drops for somebody who was baffled. A small advance but an important one.
Here’s a howler in The Independent 6 October 2010:
“Polling to accompany the report, seen by The Independent, found that over the past five years the number of people agreeing that they “really care about the house being clean” has fallen by 4 per cent to 77 percentage points. Over the same period, the number who liked to have their floors “spotless” dipped by the same amount to 51 percentage points.”
The writer knows there are percentages and percentage points: good. But they don’t know how to handle them.
It should be “has fallen by 4 percentage points to 77 per cent…dipped by the same amount to 51 per cent.”
The per cent is a standard measure: if the other were 100 what would this be? And the percentage point is the difference between two per cents. If it was 81 per cent and fell to 77 per cent then it fell 4 percentage points: not 4 per cent.
More on this in our forthcoming Reading Accounts online course and a special on calculating percentages which we’re working on.