A list of the top 30 city economies released by the market research company Askci Consulting has been published by many media outlets, catching people's attention. Beijing Youth Daily comments:

Shanghai ranked first on the list, as its gross domestic product in the first half of the year was 1.56 trillion yuan ($227 billion), followed by Beijing (1.41 trillion yuan) and Shenzhen (1.11 trillion yuan).

But although the list shows the economic scale of these cities, it does not reflect the quality of the city economies or the sustainability of their growth.

The central authorities stress that China's economy has transformed from quantitative growth to qualitative growth. But the list still employs the old GDP criteria to rank the cities according to the size of their economies, without providing any clues to the structure and quality of their economies or growth models.

It is easy to boost growth through investment. But that kind of growth is less sustainable in the long run than economic development driven by innovation and consumption.

For the cities whose economies witnessed robust growth in the first half of this year, which include Wuhan, Xi'an and Zhengzhou, it is too early to predict they can maintain the momentum in the second half of this year, as they face increasing uncertainties as their growth has relied heavily on investment attracted by their competition for capital and talent.

The media outlets should focus more on analyzing the quality of the 30 cities' economies than purely ranking them according to their economic scale.

The list also highlights that there is no system of indicators for analyzing the quality and sustainability of the city economies, which the Central Economic Work Conference called for last year and which is of great importance for assessing the performance of local officials.

The institutes, think tanks and universities should waste no time in developing such a system to focus on the quality rather than the quantity of the economic growth.