Table 1 Summary of sampling methods used, outline of sampling technique and example of how the sampling technique relates to real field survey and DSS designs.
From: Population survey sampling methods in a rural African setting: measuring mortality
Sampling Method | Technique | Example situation in field surveys |
|---|---|---|
Simple Random | Step 1: Assign a random number to each sampling unit | Cross-sectional surveys within DSS settings |
Step 2: Sort sampling units by their random number | ||
Step 3: Select sampling units in ascending order of random numbers until desired sample size is reached | ||
Probability Proportional to Size | Step 1: Assign a random number to each sampling unit | |
Step 2: Multiply the population of each sampling unit by the random number | ||
Step 3: Sort sampling units on the number generated in Step 2 | ||
Step 4: Select sampling units in descending order of number generated in Step 2 until desired sample size is reached | ||
Proportional Stratified Sampling | Step 1: Determine the proportion of sampling units needed in each strata | Cross-sectional surveys within DSS settings or establishing a DSS |
Step 2: Assign a random number to each sampling unit | ||
Step 3: Select sampling units from each strata using simple random methods until the desired sample size and ratio between strata is obtained | ||
Multi-stage Sampling (Stage 1 random; Stage 2 random) | Step 1: Randomly select geographical area for sampling | Establishing a DSS |
Step 2: Assign a random number to each sampling unit in the selected area | ||
Step 3: Sort sampling units by their random number | ||
Step 4: Select sampling units in ascending order of random number until desired sample size is reached | ||
Multi-stage Sampling (Stage 1 random; Stage 2 PPS) | Step 1: Randomly select geographical area | |
Step 2: Assign a random number to each sampling unit in the selected area | ||
Step 3: Multiply the population of each sampling unit by the random number | ||
Step 4: Sort sampling units on the number generated in Step 3 | ||
Step 5: Select sampling units in descending order of number generated in Step 3 until desired sample size is reached | ||
Geographically Dispersed (Stage 1 random; Stage 2 random; Stage 3 random) | Step 1: Randomly select two geographical areas | Multi-centre study |
Step 2: Assign a random number to each sampling unit in each of the selected areas | ||
Step 3: Sort sampling units by their random number | ||
Step 4: Select sampling units in ascending order of random number until 50% of the desired sample is selected from each geographical area | ||
Geographically Dispersed (Stage 1 random; Stage 2 random; Stage 3 PPS) | Step 1: Randomly select two geographical areas | |
Step 2: Assign a random number to each sampling unit in each of the selected areas | ||
Step 3: Multiply the population of each sampling unit by the random number | ||
Step 4: Sort sampling units on the number generated in Step 3 | ||
Step 5: Select sampling units in descending order of number generated in Step 3 until 50% of the sample is selected from each geographical area |