[Selection of DSP points in second stage and their presentation].

The principal of selecting DSP points is discussed. Because social and economic development is not balance, developing level of health business and health situation of population are obvious varies in different areas of China. In order to ensure that health information from surveillance population can be used to infer health situation of national population, the feature of geographic, administrative areas and various health situation in different areas are considered. The principals of selecting DSP are: 1. To assure well-balance of geographic distribution of DSP. 2. To assure well-balance of distribution of DSP in different kind of areas, according to above 9 index, GNP, illiterate rate, birth rate, infant death rate, rough death rate, ratio of 0-14 years people to total people, ratio of about 65 years people to total people, ratio of labor in industry to total people, and ratio of labor in agriculture to total people. The way of select DSP is: Multistage stratified random sampling (PPS). Meanwhile in order to avoid systematic error, about 15% points which are no qualified were changed. Therefore whether data from DSP can be represented health level of population of whole nation has been tested. The conclusion is that the data from DSP can indeed do so.