BEIJING (Reuters) - Global investors worried about a cut to China's official economic growth forecast to 7.5 percent this year would do well to remember the maxim of asset strippers everywhere: the sum of the parts is worth more than the whole.
In China, it's about 4.6 trillion yuan (460 billion pounds) more.
That's the difference between the 51.77 trillion yuan in gross domestic product reported in aggregate by China's 31 provinces in 2011 and the official 47.16 trillion yuan captured in the methodology used by the National Bureau of Statistics, a quirk of calculation roughly equivalent to the GDP of Turkey.
Run the corporate raider's slide rule over forecasts for growth in 2012 and yet another disparity emerges: the weighted average of the individual provinces comes to 10.3 percent.
Even a more pedestrian model subtracting the 4 percent inflation target from the money supply growth forecast at 14 percent still implies economic expansion of 10 percent.
For reform-minded Premier Wen Jiabao, it brings a second maxim into play: you can get too much of a good thing.
Unbridled growth is making it hard to rebalance an economy that, while the world's second-largest, has become worryingly dependent on exports and foreign investment -- vulnerable to such vagaries as the European debt crisis and subpar U.S consumption.
Its heavy reliance on capital spending is also stoking a highly polluting manufacturing sector prone to excess capacity, while its property and financial markets appear perennially on the verge of speculative bubbles that could threaten social stability.
But reining in and transforming the economy is particularly difficult in a one-party system where posting impressive growth numbers has been the only sure-fire way to achieve political promotion through the Communist Party ranks.
"Clearly they want to signal that they want to change the growth model. But to change the growth model, you need to do a lot more than lowering your growth target," said Stephen Green, an economist at Standard Chartered Bank in Hong Kong.
"The system hasn't changed. It's still all about stronger growth, getting promoted on the back of growth," he said.
So while most provincial leaders have trimmed targets to show support for the national leadership, the personal incentive to outperform keeps them well above Beijing's mandated rate.
So, too, does the need to generate revenue to pay back 10.7 trillion yuan in local government debt.
"Local governments cannot generate fiscal revenues without economic growth," said Li Ruogu, head of Export-Import Bank of China, a state-run policy bank.
Officially, China is targeting just 7 percent economic growth on average in 2011-2015, under the 12th five year plan.
But even the export hub of Guangdong -- China's largest provincial economy with GDP roughly equal to the Netherlands, the world's 16th biggest economy -- has set a 2012 growth target of 8.5 percent, typifying the uphill battle the government faces in its bid to transform the economy.
Only the wealthiest provinces and cities including Beijing, Shanghai, Guangdong and Zhejiang have growth targets below 10 percent, while the southwestern province of Guizhou -- one of the country's poorest -- leads the quest for growth by aiming for 14 percent expansion this year.
China's growth nationwide is on track to slow to just over 8 percent in the first quarter of the year, analysts say, although they reckon the full year will see 8 to 9 percent growth.
Faster growth for the likes of Guizhou fits into government plans to help the interior of the vast country of 1.3 billion people catch up economically with the long-booming coast.
But the justification is not so clear-cut for the already affluent eastern province of Fujian, which aims for 11 percent growth in 2012 to catch up with its richer-still neighbours Guangdong and Zhejiang.
Fujian Communist Party chief Sun Chunlan's rationale for the brisk pace parroted Beijing's own basic policy course for the year: "maintaining stability while seeking advancement".
"We aim to grow as fast as possible while ensuring good quality," Sun told reporters on the sidelines of China's annual parliament meeting, the National People's Congress, in the wake of Wen's modest growth forecast.
It's the quality of growth that is Beijing's quandary.
Its reliance on pollution-belching, energy-guzzling factories persists even as China grows richer, and it is walking a policy tight-rope on an investment-driven real estate boom that -- despite fears of a destabilising bubble -- remains a key driver in the economy.
The ratio of total fixed-asset investment to GDP grew to 66 percent in 2011 from 57 percent in 2008 and 38 percent in 2001.
Liu Mingkang, the country's former banking regulator, said the overcapacity in many Chinese industries was shocking.
"If we cannot change the situation, we will find that energy consumption will not fall, power saving and emission reduction will be difficult to achieve and bank lending can never be enough," he said.
(Editing by Nick Edwards and Edmund Klamann)