Just because X is stated to be true by a government does not make it true.
This is most clearly seen in war time: "The first causality of war, is always truth."
That is true, but in similar fashion, some nutcase, partisan or scoundrel posting something on the web doesn’t make it true either. In the case of government and in specifically in this case, there are no secrets. None of this material, including source material is secret. It compiled and published by the government. It is reviewed and scrutinized by business professionals and academics – all the time.
The current CPI, GDP methodology is the one the US government used a little more than two decades ago. The US's GDP is nearly meaningless index. For example: If I sell my dog to James for two million dollars and he sells me his two cats for one million each, we make a 4 million increase in the calculated GDP.
How many people do you know who sell their dogs and cats for two million dollars each just to jack up a GDP number? And even if they were crazy enough to do so, how many dogs and cats would they have to sell and buy to make a material impact on a 16 trillion dollar economy? The CPI and GDP measures are long established and the methodology. It is used because of its predictive powers. If it were somehow flawed, it would be quickly noticed in academia and in the business world.
I have long contended that GDP should not include ballgame & movie tickets, hair cuts, etc. that have no value a year later. I.e. a "durable GDP," DGDP, would be much more meaning full.
By a DGDP index, Chinese economy is at least twice that of the US, now.
Well you can contend that all you want. But the money spent on baseball games, haircuts, and movie tickets doesn’t stop being money just because you don’t like how it is being spent. The GDP is a measure of the entire economy, not portions of the economy. If you want limited or measures of specific sectors, the government publishes those numbers as well. If you want durable goods, the government reports on durable goods as well. http://www.census.gov/manufacturing/m3/adv/pdf/durgd.pdf
So basically, what you are doing is taking a subsection of the GDP and calling it the entire GDP. That is misleading, it isn’t honest. If you want to ignore parts of the economy, if you want to mislead yourself, go for it. But don’t mislead others.
And there is no “durable goods domestic product index”. There is a durable goods portion of the GDP. If businessmen and academics wanted to talk about durable goods instead of GDP, they could, but they don’t. They use both, because each tells them a portion of the economic story. But one does not replace or diminish the other.
And your notions about China’s economy are equally nonsensical. The US economy is more than twice the size that of China – not to mention China faces a number of large and potentially devastating road bumps, including but not limited to governmental instability and demographic changes that are about to bite it in the derriere.