The most fundamental criteria for measuring the progress and development of a society are whether the society can well meet the needs of the people, whether it can provide a broad and free development space for the people, and whether it adheres to the people-oriented approach to social development goals. Judging from the past, the practice of indicators such as GD. P that reflect economic development as the core indicator of social development progress is obviously inadequate, and the happiness index that reflects the subjective quality of life of the public can make up for the lack of GD. P indicators and is used to Not only that, we measure the overall progress and development of society. The happiness index is also an important indicator for monitoring the healthy operation of a society. It plays a diagnostic function and reflects the happiness index of the people. It is the fundamental basis for us to formulate and adjust various policies. We can Through tracking research on the happiness index, grasp the trend and change law of the happiness index of different social groups, use it as an important "indicator" of the degree of reform target realization, understand the "barometer" of people's mood fluctuations and changes, and detect the healthy operation of society "Early Alerter". What does this text mainly introduce about the happiness index? ['It is an important diagnostic tool for detecting the operation of society.', 'Help people rationally grasp and understand social conditions.', 'It has important practical value for promoting social development and progress.', 'The GD. P indicator should be replaced as the core indicator of social progress.']