Brief Introduction
I. Main Contents
Data in this chapter show the people’s living conditions and their changes in China, mainly including basic conditions, living status, income and expenditure, and housing of households.
II. Sources of Data and Methodology on Survey
Data of 2013 and after come from Household Survey on Income and Expenditure and Living Conditions. Data from 1978 to 2012 are estimated based on the historical data of Urban Household Survey and Rural Household Survey according to the comparable definition and coverage of main income and consumption indicators of Household Survey on Income and Expenditure and Living Conditions.
1. Methodology of Household Survey on Income and Expenditures and Living Conditions
In the fourth quarter of 2012, NBS launched reform on the household survey programme, to develop an integrated survey, instead of the two separate urban and rural household surveys. Main contents of the survey include: income and expenditure of households, employment, social security participation, housing, family operation, production, investment, and factors affecting the income distribution.
The survey is conducted by randomly selecting village-level units, small enumeration area and surveyed households, adopting the sampling method of combining stratification, multi-stage, probability proportional to population size and systematic sampling,with all households in a province as the population. More than 1.6 million households in 16,000 communities of 1,800 counties in the country are selected, and surveyed for pre-investigation. On this large sample, about 160,000 households are selected by systematic sampling for diary-keeping. Selected communities and households are rotated regularly.
Survey on Income and Expenditures and Living Conditions is so designed that the sampling error should not exceed ±1%, with a confidence probability of 95%. Income and expenditure data are collected with household diaries as the main source, assisted by questionnaires to collect other relevant data. All field work is conducted independently by local survey offices under NBS. Coding, checking, data entering are conducted by survey offices at city level with the unified methods and data processing program, and then household basic data are transferred to NBS for final tabulation.
Starting from 2013, NBS collected diary accounts of 160,000 households for 12 months, and tabulated national disposable income of all residents, urban residents and rural residents, with this system of Household Survey on Income and Expenditures and Living Conditions.
2. Methodology of Urban Household Survey
Urban Household Survey was conducted by the Office of Urban Household Surveys of the NBS prior to 2012. The main contents of the survey included persons in the household and the household composition; cash income and expenditure of the household; quantity of major commodities purchased and expenditure; the employment of household members; the housing condition; and the possession of durable consumer goods.
The survey covered only non-agricultural households prior to 2001. From 2002 to 2012, the survey covered the households in district areas of all city and county towns.
Sample cities and towns in urban areas were selected by using stratified random sampling method. Firstly, all the urban areas and towns of all provinces (autonomous regions and municipalities directly under the Central Government) were stratified into three strata according to population size: large and medium-sized cities (at and above prefecture level), county-level cities and county towns. Secondly, the sample size was decided by proportion of population in selected stratus to the provincial total. Thirdly, cities and towns were arranged in ranking the annual average wages of the employed persons, then with the accumulative population in each city and town sample cities and towns were selected by systematic sampling scheme according to the size of the samples.
The selection of sample households in urban areas was done by two steps: the first step was to conduct an ad hoc large sample survey; the second step was to select a small sample from the large sample, to be used as regular sample households for diary-keeping.
The ad hoc survey with large sample was conducted every three years; with the objective of providing sample frame for regular surveys and basic information for data evaluation of regular surveys. In the large sample survey, samples in sampled cities and towns were selected with stratified two (multi)-stage and probability proportional to size (PPS) method. Namely, stratification was done at district level, and then PPS sampling method was used to select sample communities/resident’s committees, and finally the systematic sampling method was used to select dwellings from the selected communities/resident’s committees. In some large cities, three-stage sampling method was used. Firstly, the communities/resident’s committees were selected. Secondly, small enumeration areas were selected. Thirdly, sample dwellings were selected. A survey would be conducted to the large samples or the first phase samples to collect relevant information on population, persons employed, income and so on of the households. Then grouping is made based on the information collected, small samples or the second phase samples were selected according to proportions which were regular sample households to keep diary.
The national sample included 66,000 households at the end of 2012.
3. Methodology of Rural Household Survey
Rural Household Survey was organized by the Office of Rural Household Survey of the NBS prior to 2012. The main contents of the survey included basic condition of rural households, housing conditions, income, consumption expenditure, consumption of major consumer goods and the quantity of durable consumer goods owned.
Sample survey on rural households was conducted by first selecting sampled villages and then selecting households in the selected villages in each province, with all rural households in the province as the population. A combination of various sampling approaches is used to identify a sample of 74,000 households selected from 7,000 villages throughout the whole country.
The survey was so designed that the sampling error should not exceed ±3%, with a confidence probability of 95%. In order to ensure the accuracy of the survey data on the rural households, two accounts were designed for the respondent households by the Office of Household Survey of the NBS: the cash account and the account on goods in kind. Nearly 10 thousand assistant interviewers were recruited to help the households keep good accounts and to check on a timely basis, and to check and tabulate data from the survey.
In order to overcome the tedium of respondent households and to ensure that the sample was accurately representative over time and reflected the changing rural social and economic situation, a 5-year sample rotation scheme was implemented.