title: [Re-examination sampling methods of national immunization survey for national immunization program vaccines coverage at the township level by the national level in 2013, China].
abstract: OBJECTIVE
  To review the re-examination sampling method and procedure of national immunization survey for the national immunization program vaccines coverage at the township level by the national level in 2013, China.
  
  
  METHODS
  According to the result of immunization coverage at the township level through self-assessment by county, all townships were stratified by whether a township with ≥ 90% immunization coverage for the second dose of measles-containing vaccines (MCV2), and a township was urban or rural. After then, 2 townships for each province were randomly sampled from those strata through the surveyselect procedure of the statistics analysis system 9.2 (SAS 9.2).
  
  
  RESULTS
  64 townships were randomly sampled from 32 provincial units for the re-examination, i.e. an urban township and a rural township each province, of which there were 38 townships with ≥ 90% MCV2 coverage and 26 townships with < 90% MCV2 coverage. There were 24 urban townships, 2 rural townships with < 90% MCV2 coverage and 8 urban townships, 30 rural townships with ≥ 90% MCV2 coverage, respectively.
  
  
  CONCLUSIONS
  Based on the information of the self-assessment result of immunization coverage survey by counties, Stratified randomized sampling were employed for the re-examination through the Surveyselect procedure of statistics analysis system (SAS) to implement the sampling procedure. This can enhance the sampling efficiency, ensure the randomness of the sample, and make the survey much more representative and comparable.
authors: Department of National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
authors: Lei
authors: L
authors: Cao
authors: Department of National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing 100050, China; Email: zhengjsh@foxmail.com.
authors: Jingshan
authors: J
authors: Zheng
authors: Department of National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
authors: Lingsheng
authors: L
authors: Cao
authors: Department of National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
authors: Ping
authors: P
authors: Yuan
authors: Department of National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
authors: Jian
authors: J
authors: Cui
authors: Department of National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
authors: Huaqing
authors: H
authors: Wang
authors: Department of National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
authors: Li
authors: L
authors: Li
mesh_terms: D002681:China; D006801:Humans; D007114:Immunization; D017589:Immunization Programs / Q000706:statistics & numerical data*; D008458:Measles Vaccine; D012424:Rural Population; D012494:Sampling Studies; D011795:Surveys and Questionnaires; D014505:Urban Population; D014611:Vaccination / Q000706:statistics & numerical data*; D014612:Vaccines
chemical_list: D008458:Measles Vaccine; D014612:Vaccines