Editing Cluster sampling (section)

==Applications of cluster sampling==
An example of cluster sampling is [[area sampling]] or [[geographical cluster sampling]]. Each cluster is a geographical area in an [[area sampling frame]]. Because a geographically dispersed population can be expensive to survey, greater economy than simple random sampling can be achieved by grouping several respondents within a local area into a cluster. It is usually necessary to increase the total sample size to achieve equivalent precision in the [[estimator]]s, but cost savings may make such an increase in sample size feasible.

For the organization of a population [[census]], the first step is usually dividing the overall geographic area into enumeration areas or [[Census tract|census tracts]] for the field work organization. Enumeration areas may be also useful as first-stage units for cluster sampling in many types of surveys. When a population census is outdated, the list of individuals should not be directly used as [[sampling frame]] for a socio-economic survey. Updating the whole census is economically unfeasible. A good alternative may be keeping the old enumeration areas, with some update in highly dynamic areas, such as urban suburbs, selecting a sample of enumeration areas and updating the list of individuals or households only in the selected enumeration areas.<ref>{{Cite web |title=HANDBOOK ON Master Sampling Frames for Agricultural Statistics - PDF Free Download |url=https://docplayer.net/18720914-Handbook-on-master-sampling-frames-for-agricultural-statistics.html |access-date=2024-01-10 |website=docplayer.net}}</ref> 

Cluster sampling is used to estimate low mortalities in cases such as [[war]]s, [[famine]]s and [[natural disaster]]s.<ref>David Brown, [https://www.washingtonpost.com/wp-dyn/content/article/2006/10/10/AR2006101001442.html Study Claims Iraq's 'Excess' Death Toll Has Reached 655,000], ''Washington Post'', Wednesday, October 11, 2006. Retrieved September 14, 2010.</ref>

=== Fisheries science ===
It is almost impossible to take a [[simple random sample]] of fish from a population, which would require that individuals are captured individually and at random.<ref>{{cite journal |last1=Nelson |first1=Gary A. |title=Cluster Sampling: A Pervasive, Yet Little Recognized Survey Design in Fisheries Research |journal=Transactions of the American Fisheries Society |date=July 2014 |volume=143 |issue=4 |pages=926–938 |doi=10.1080/00028487.2014.901252|bibcode=2014TrAFS.143..926N }}</ref> This is because [[fishing gear|fishing gears]] capture fish in groups (or clusters). 

In commercial fisheries sampling, the costs of operating at sea are often too large to select hauls individually and at random. Therefore, observations are further clustered by either vessel or fishing trip.

=== Economics ===
The [[World Bank]] has applied adaptive cluster sampling to study informal businesses in developing countries in a cost efficient manner, as the informal sector is not captured by official records and too expensive to be studied through simple random sampling.<ref>{{cite journal |last1=Aga |first1=Gemechu A. |last2=Francis |first2=David C. |last3=Jolevski |first3=Filip |last4=Rodriguez Meza |first4=Jorge L. |last5=Wimpey |first5=Joshua S. |title=An Application of Adaptive Cluster Sampling to Surveying Informal Businesses |journal=Journal of Survey Statistics and Methodology |date=January 2023 |volume=11 |issue=5 |pages=1246–1266 |doi=10.1093/jssam/smac037}}</ref> The approach follows a two-stage sampling whereby adaptive cluster sampling is used to generate an estimate of the universe of informal businesses in operations, while the second stage to obtain a random sample about the characteristics of those businesses.