Political scientist Jeremy Wallace has a recent paper on this topic:
Economic statistics dominate policy analyses, political discussions, and the study of political economy. Such statistics inform citizens on general conditions while central leaders also use them to evaluate local officials. Are economic data systematically manipulated? After establishing discrepancies in economic data series across regime types cross-nationally, I dive into sub-national growth data in China. This paper leverages variation in the likelihood of manipulation over two dimensions, arguing that politically sensitive data are more likely to be manipulated at politically sensitive times. GDP releases generate headlines, while highly correlated electricity production and consumption data are less closely watched. At the sub-national level in China, the difference between GDP and electricity growth increases in years with leadership turnover, consistent with juking the stats for political reasons. The analysis points to the political role of information and the limits of non-electoral accountability mechanisms in authoritarian regimes as well as suggesting caution in the use of politically sensitive official economic statistics.
All good points. I would stress, however, that Chinese statistics have many problems in them and so they are not simple overestimates of how the economy is doing, at least not over the last thirty years as a whole. In some ways Chinese growth statistics have been, until 2008-2009, probably underestimating the actual progress on the ground. In general, growth figures underestimate progress when changes are large, and overestimate progress when changes are small. (One reason for this is that extreme progress brings a lot of new goods to the market and their marginal value is underestimated by their price ex post, since it is hard to adjust for the fact that the price ex ante was infinite or very high.) In Western history for instance, our most significant period of growth was probably the late 19th through early 20th century, when the foundations for the modern world were laid, yet estimated growth rates for this period are not astonishingly high. We’re missing out on the values of the new goods, for one thing.
For the pointer I thank Henry Farrell.