Multi-stage sampling represents a more complicated form of cluster sampling in which larger clusters are further subdivided into smaller, more targeted groupings for the purposes of surveying. Despite its name, multi-stage sampling can in fact be easier to implement and can create a more representative sample of the population than a single sampling technique. Particularly in cases where a general sampling frame requires preliminary construction, multi-stage sampling can help reduce costs of large-scale survey research and limit the aspects of a population which needs to be included within the frame for sampling.
In traditional cluster sampling, a total population of interest is first divided into ‘clusters’ (for example, a total population into geographic regions, household income levels, etc), and from each cluster individual subjects are selected by random sampling. This approach however, may be considered overly-expensive or time consuming for the investigator. Using multi-stage sampling, investigators can instead divide these first-stage clusters further into second-stage cluster using a second element (for example, first ‘clustering’ a total population by geographic region, and next dividing each regional cluster into second-stage clusters by neighborhood). Multi-stage sampling begins first with the construction of the clusters. Next, the investigator identifies which elements to sample from within the clusters, and so on until they are ready to survey.
In Iyoke et al. (2006) Researchers used a multi-stage sampling design to survey teachers in Enugu, Nigeria, in order to examine whether socio-demographic characteristics determine teachers’ attitudes towards adolescent sexuality education. First-stage sampling included a simple random sample to select 20 secondary schools in the region. The second stage of sampling selected 13 teachers from each of these schools, who were then administered questionnaires.
Agresti A, and Finlay, B. (2008) Statistical Options for the Social Sciences, 4th edition. (Upper Saddle River, NJ: Prentice Hall).
Food and Agricultural Organisation of the United Nations (FAO) (1997). Chapter 7: Sampling In Marketing Research. In Marketing research and information systems. (Marketing and Agribusiness Texts - 4). Agriculture and Consumer Protection, FAO. Retrieved from http://www.fao.org/docrep/W3241E/w3241e08.htm#cluster%20and%20multistage%20sampling
Iyoke, C.a et al. (2006) “Teachers’ Attitude is Not an Impediment to Adolescent Sexuality Education in Enugu, Nigeria.” African Journal of Reproductive Health/La Revue Africaine de la Santé Reproductive 10 (1): 81-90