One of the more bizarre things to pop up in the past couple of days is the idea that data revisions by a statistical agency is a “mistake” and thus cause to fire the head of a statistical agency. No, that is not how data revisions work. Not all economic data are revised. The most important non-revised data are those in consumer price index reports: prices during the month are measured, and then the monthly price indices are calculated in one shot. (There is the chance of an error causing a revision.) Since the CPI is used in contracts, a lack of revisions is important. Surveys with random sampling also tend to not be ... (full story)