During the economic gains stage, well-being is sensitive to economic growth, and the two increase in tandem. During the lifestyle changes stage, economic growth has little impact on well-being. Once incomes reach a certain level, subjective happiness and GDP growth show no clear positive correlation.

Inglehart places the boundary between these two stages at an income of $5,000 at 1995 purchasing power parity (PPP). In 2009, that was equivalent to $7,038, and in 2010 China's per-capita GDP is thought to have passed that level. And so China has, by these figures, already entered the stage where well-being is insensitive to economic growth. This means that policies designed to increase well-being cannot focus on GDP alone. For this reason, research into national happiness will be an important factor in China's public-policy decisions as the nation reaches middle-income levels.

A national happiness index with Chinese characteristics should have a role in this process. Back at the start of China's period of reform and opening-up, the nation identified a well-off society as a development aim - and the government promised to create that society. The proposed index would not only provide a more comprehensive measure of the development of that society, but also a new way of assessing government performance.

Governments are the planners and implementers of development. And they have a duty to increase the happiness of those they govern. Governance focused on the "comprehensive raising of the people's sense of well-being" would be a demonstration of socialism with Chinese characteristics - the system intended by Deng Xiaoping's market reforms - and increase the degree to which the Chinese government is seen to be governing for the people. The following recommendations are for putting together a Chinese National Happiness Index:

First, the index should reflect China's national characteristics. Many nations are in the process of trying to build similar indices, and there is no standardized measure. I believe that differences in culture and traditions during the development process mean that these indices should reflect national characteristics.

Second, while the index should be comprehensive, it should not include too many factors. The index must cover the content of the Human Development Index - per-capita GDP, life expectancy and educational level - as well as important factors in development such as governance, environmental quality, sense of security, social capital and distribution of income. Selection of indices should reflect the key variables in the development of the above factors.

Third, the index should include subjective as well as objective measures. The main difference between a happiness index and classical development rankings is the inclusion of subjective measures, allowing citizens of a country to assess the factors that are hard to capture objectively - environmental satisfaction, sense of security, satisfaction with local government and so on.

Fourth, we must encourage local implementation. A number of local governments are already working on these issues, including Chongqing in western China and Jiangyin on the east coast. Their experiments use a well-being centered approach to assess government performance. Such systems will encourage officials to use public resources in ways that increases happiness and boost the people's satisfaction with local government.

The author is professor at the Chinese Academy of Sciences and Tsinghua University. The article was originally carried on www.chinadialogue.net, a bilingual website dedicated to environment issues.