When strategies are developed to structure a survey sampling plan, there are multiple sampling methods available for consideration - including both probability and non-probability sampling. In the next part, you can learn more about survey sampling statistics and methods.
Probability Survey Sampling Methods:
- Simple Random Sampling – In this method, a random selection procedure is followed to ensure each member or object in the population has the same chance of getting selected into the sample.
- Systematic Sampling – In this sampling method, a random starting point is chosen and a constant skip interval is marked for the selection of respondents for the sampling process. This method is often easier than the aforementioned sampling method. The formula of the skip interval is population size divided by sample size..
- Cluster Sampling – For cluster sampling, the population is divided into clusters. Within the clusters the sampling units are usually similar to each other. After defining the clusters, different sampling methods can be applied to sample from them. Sampling statistics are collected from those clusters that are in the sample. Area sampling is an important form of cluster sampling.
- Stratified Sampling – This method is best for places where the population is not uniform. Here the the sampler divides the population into strata based on qualities such as gender, income, field size, etc., and then performs a survey in each stratum. Lastly, weights are applied for estimating the population's properties.
Non-Probability Survey Sampling Methods:
- Convenience Sampling Method – This plan is used where reaching people is easy and convenient (e.g. a mall). Issues arise if part of the population of interest does not visit the chosen area, since they won't be part of the survey.
- Judgment Sampling Method – In this method, the researcher judges and decides who are to be included in the sample based on his/her knowledge about the population. This process is highly subjective, so the probability of errors is high. This method is used to recruit focused groups.
- Referral Sampling Method – Also called
Snowball Sampling, is often proposed when the targeted population is small compared to the frame. When the sampler finds a member of the target population, the sampler uses the member to find more members of the target population. The detriment of this method is that parts of the population that are unfamiliar or disliked or have different opinions might not be included in the sample.
- Quota Sampling Method – In this method, a designated number of people with certain specific characteristics are sampled (e.g. 1000 Caucasian men and 1100 Caucasian women).
All these sampling methods are preferred and followed by statistical consultants in USA to give strong results from surveys performed by researchers or for researchers. So, get connected to the best consultants of USA and get better direction for your business growth.