6.2. Need for and use of a sampling frame in random sampling
Implementation of random sampling generally requires a list of sampling units, the sampling frame, from which to select the sample by random means, although systematic sampling can in some cases be carried out without one. This operates using a numbering system for each person listed. Random selection without replacement of the required sample size from the list of numbers of those having given permission for their records to be used for the purposes of sampling identifies the selected numbers and hence the sample selected, where a simple random sample is required.
For a stratified design, sub-samples are selected in the same way from each stratum, by selecting each sub-sample separately from the list of identifying numbers for those belonging to the relevant stratum. A cluster sample might select a few local beekeeping associations randomly from a centrally held list of associations, as for a simple random sample, and either target everyone in the selected associations as a survey participant, or take a further random sample from the membership list of each local association again using random selection of numbers as the means of sampling.