How to calculate:
In Beijing, for example, the consumer price index is calculated by surveying the prices of more than 600 specifications of commodities and service items in nearly 300 commercial outlets in Beijing, calculating the indices of more than 600 representative products, and then geometrically averaging 251 basic classification indices, and then using the amount of consumer spending as the weights, and then summarizing the consumer price index by the composite formula. The specific steps are as follows:
1. Select representative specifications. The current national methodological system specifies the content of the survey to 251 basic classifications, and the minimum number of representative specifications included under each basic classification. The representative specifications are determined by the provinces and cities themselves, and some specifications with local consumption characteristics can also be added appropriately. In accordance with the principle of selecting representative specifications, the city has identified more than 600 specifications of goods and services as representative specifications for the calculation of the consumer price index. Once the representative specifications are determined, they cannot be replaced during the year.
2. Sampling of price survey points. First of all types of commercial outlets sales from high to low queue, and then isometric sampling. To take into account both large and small stores, a variety of economic types, comprehensive stores and specialized stores, a variety of commercial formats, reasonable layout and other factors, the sampling results do some corrections. The city **** selected nearly 300 commercial outlets as price survey points. Price survey points are adjusted once a year.
3. Calculate the weights of the consumer price index. The weights are indicators that reflect the degree of influence of price changes of surveyed goods or services in the formation of the total index, and are calculated on the basis of the proportion of total expenditures on various goods or services spent by households. The information on the weights comes from the data on per capita consumer expenditures of residents in the Urban Household Survey statistics. The weights for the basic classification and above categories are fixed for one year.
4. Price survey and calculation of average price. According to the degree of relevance of goods or service items to people's lives and the frequency of price changes, the number of price surveys is determined. Fresh vegetables, fresh fruit, meat, poultry and eggs, aquatic products and other prices, every 5 days of investigation; food, oil, tobacco, alcohol and beverages, catering and other wearing goods prices every 10 days of investigation; national and local government pricing of commodities or service items of the price, every 15 days of investigation. Price surveys are timed, fixed-point, fixed-person direct surveys.
Price information collected, but also to calculate the monthly average price. That is, each representative of the specifications of all survey points of the point in time the price of a simple arithmetic average, to get the average monthly price. For example: the price of a certain type of clothing survey three times a month, there are six survey points, that is, the 18 point-in-time prices are added, and then divided by 18.
5. Calculate the consumer price index. Once the monthly average price is calculated, the monthly price index compared to different base periods can be calculated. First, the calculation of the price index of a single commodity or service item, and then the single index for the geometric mean, the calculation of the basic classification of the price index, the basic classification of the index and then sequentially weighted to calculate the class index and the total index.