Yesterday, The Evening Standard published a front page story about its exclusive poll of Londoners - revealing how almost eight out of ten (78%) people think mayoral candidate Boris Johnson is fighting on behalf of wealthy people more than any other group.
Today, the newspaper published a correction at the bottom of page 2 saying they had "failed to apply the correct sample weighting". The real number is 37%.
Anyone in PR will be feeling weird right now.
On one hand, we all know the power of a good survey and are applauding the Evening Standard for commissioning YouGov to test how real people are feeling about an important issue.
On the other, we all know how hard it is to interpret survey results, and live in fear of this kind of mistake.