[Cluster sampling in health surveys].
OBJECTIVE
Describing how the cluster sampling statistical technique can be applied to health surveys.


METHODS
The article describes the most important aspects for each methodological step, emphasising cluster sampling's foundations. It was applied to a population of around 100,000 inhabitants from commune 18 in Cali. The sample covered 30 city blocks and 3,026 people were interviewed. The information was gathered using the Community-based Information System for Primary Health Attention.


RESULTS
The sampling technique produced precise and reliable information for estimating population health event prevalence in a cross-sectional study. Sampling error was 2.5 % in the general population, 10% in children aged less than 5 years, 5.7% in children aged 5 to 14, around 3.0% in those aged 10 to 59 and 7.2% in the population aged more than 60.


CONCLUSIONS
The method guaranteed a 2.5% sampling error in estimating general population prevalence and less than 10% sampling errors for established population groups.
Facultad de Medicina, Fundación Universitaria San Martín, Cali, Colombia. zapatahelmer@gmail.com
Helmer de Jesús
Hde J
Zapata-Ossa
Angela M
AM
Cubides-Munévar
María C
MC
López
Elisa M
EM
Pinzón-Gómez
Paola A
PA
Filigrana-Villegas
Carlos A
CA
Cassiani-Miranda
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003105:Colombia; D003430:Cross-Sectional Studies; D005260:Female; D006304:Health Status; D006306:Health Surveys / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D012494:Sampling Studies; D015983:Selection Bias; D055815:Young Adult