Some used a 1930s mathematical tool called Benford's Law to argue that the data was unreliable.
But China hit back defending its numbers.
In fact, every time China unleashes its economic indicators we see this debate pop up.
And with the country unleashing its first massive data dump for the year late Thursday, Business Insider thought it would be a good time to rerun its feature on the most reliable Chinese economic indicators according to the experts.
Electricity consumption data is unlikely to be inflated because it would lead Beijing to impose restrictions on energy use
Moody's economist Alaistair Chan, Bank of America's Ting Lu, and future Chinese premiere Li Keqiang have pointed out that electricity consumption tends to be one of the more reliable economic indicators in China.
Lu has previously said there is little reason for electricity consumption to be manipulated. "China's local officials might be incentivized to over-report some macro indicators such as GDP and FAI, but they have little incentive to over-report use of energy including electricity as Beijing imposes increasingly restrictive regulations on energy use per unit of GDP on local governments."
The official and HSBC PMI numbers generally match the true growth numbers
Chinese HSBC purchasing manager's index (PMI) and official PMI are said to be fairly reliable. The relative weakness in the HSBC PMI number has been attributed to the fact that it is more exposed to small-and-medium enterprises.
Moody's analyst Alaistair Chan writes that they are "based on surveys and generally match other indicators of activity, such as industrial production and GDP" and therefore are more reliable.
Rail freight traffic may be prone to error, but not manipulation
Li Keqiang, China's future premier, who was revealed to have said that the GDP number is "man-made" in a Wikileaks report has said that rail cargo data which is less closely watched is a far more reliable indicator.
"Rail freight is useful because it is a measure of actual goods moving across the country, which is a proxy for industrial activity," according to Chan. "It is not weighted (like industrial production), which can introduce error because it measures gross weight of freight, with no distinction between say coal and cars. But it is fairly accurate and not prone to manipulation."
The OECD composite leading indicator does a great job of predicting turning points in growth
The OECD composite leading indicator was developed in the 1970s to act as an early indicator of economic activity. Chan thinks the indicator is one of the more reliable economic indicators about China.
"With the OECD composite leading indicator, we found that it is a good predictor of turning points of China’s GDP growth. The OECD has done a pretty good job in compiling a bunch of indicators that move in such a way that when the CLI changes direction it is a big signal that conditions are changing."
Export and import data can be verified by cross-checking with data from its trading partners
Many analysts point to the reliability of export and import data because it can be independently verified by comparing it with trade numbers reported by other countries.
Societe Generale's Wei Yao has previously argued that, "another advantage of import data is that they are subject to less statistical and ad hoc adjustments than industrial production and GDP, since their consistency can be cross checked relatively easily with the data from China’s major trading partners."
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