Hundreds of studies in economics misinterpret China’s sub-national population and per
capita data. The most widely used population counts are of hukou registrations from each
province, prefecture, county, or city rather than of the people living in each place and
generating local GDP. Over 220 million people have left their place of registration, while
almost none had when reforms began, creating time-varying errors in estimates of per capita
income of sub-national units. We survey empirical articles in blue ribbon journals, in
development journals, and in regional and urban economics journals that use China’s subnational
data. Over 80 percent of articles use these data erroneously; most commonly the
wrong population or employment counts are used to measure the size of sub-national units,
and per capita data are calculated with the wrong denominator for the interpretation placed
on variables. We provide examples of errors from each group of journals, and a critical test of
one highly-cited study. Specifically, we show that if hukou registrations are erroneously used
to measure the local population, following existing practice, conclusions about driving forces
for urban area expansion are reversed. We give recommendations for more careful use of
China’s sub-national population and per capita data.