But most Republicans say it amounts to creating people who don't exist. The idea is to perform a quality-check and fix the original head count based on the number and types of people missed. In a survey of 314,000 households, the bureau calculates how far off its numbers were. The bureau also examines how the errors varied according to age, race, gender, housing status and geography. The tricky part comes when the bureau takes those error rates and applies them to similar people and neighborhoods across the country.
Critics question whether the households match up with the nation as a whole.
And some are wary of glitches in the calculations. For example, a computer glitch threw off the sampling results from 1990. This time, the bureau sampled almost twice as many households, spent more time doing so, and refined its calculation methods. The procedure being used was backed by the American Statistical Association and several panels of the National Academy of Sciences. The results aren't out yet, but they are being monitored by the Academy.