Academic achievements, companions and recognition from others are the main sources of happiness for Chinese primary and secondary school students, according to the first "Chinese Children's Happy Growth Index", jointly released by four institutions on Sept 20 in Beijing.

This index analyzed the key elements of a growth in happiness — drawing on advanced theories from both home and abroad — by conducting a comprehensive quantitative analysis of the influencing factors of children's happiness.

According to the research, the average score of Chinese children's happiness growth is currently 82.22, which indicates most Chinese children are "Quite Happy".

70.1 percent of the Chinese children regard high grades in school as the greatest happiness, exceeding other factors by more than 20 percentage points.

Hanging out with friends provides enjoyment for 49.3 percent of children, ranking second.

In general, junior-grade students and children with better physical and academic records find it easier to be happy, according to the survey.

However, the results also show that 46.9 percent of the students are suffering from sleep deprivation caused by school assignments.

During the survey, 97 percent of mothers label their children as "happy", while only 92.5 percent of the children hold the same opinion.

Over 30 percent of the children say their parents play on their cellphones during parent-child conversation.

This index system was built through the analytic hierarchy process from the Internet Development Research Institution of Peking University, combining the specific national conditions and environmental features of children's learning, living and developing processes in China.

After the system construction was completed, 3,475 valid samples were collected by China Youth and Children Research Center through questionnaires from 28 primary and secondary schools in seven cities, including Beijing, Guangzhou, Nanjing, Chengdu, Liaoyang, Fuyang and Changsha.

Among the seven cities surveyed, children in Beijing — with an average happiness score of 86.10 — enjoy the highest degree of happiness, followed by Nanjing (84.66) and Guangzhou (83.15).

A gap of almost 10 points separates Fuyang — the city with the lowest score of 76.64 —and Beijing, showing that children in first-tier cities have the highest level of happiness, while third-tier cities' children enjoy the lowest.

"This study opens a window for the whole society to understand children and provides a possible approach to better foster children's happiness and well-being," said Sun Hongyan, children's department director of the China Youth and Children Research Center.

This newly-published index also provides a solid theoretical basis for scientifically promoting the healthy development of children in China, Sun added.

Li Jiayue contributed to this story.