Nonprobability Sampling: A Review
Sampling is a procedure used in research to select a subset of the population of interest, with the aim of making generalizations from the sample to the population. Nonprobability sampling is a type of sampling method in which the sample elements are not selected on the basis of randomness, and therefore, the samples are not considered representative of the population. This article provides an overview of the different types of nonprobability sampling, their advantages and disadvantages, and their application in research.
Types of Nonprobability Sampling
Nonprobability sampling can be divided into four main types: convenience sampling, purposive sampling, quota sampling, and snowball sampling.
Convenience Sampling
Convenience sampling, also known as accidental sampling, is a type of nonprobability sampling in which the researcher selects the sample from the population based on convenience. This type of sampling is typically used when the researcher has limited resources and time. The main advantage of convenience sampling is that it is relatively inexpensive and easy to implement. However, it is vulnerable to selection bias, as the sample may not be representative of the population.
Purposive Sampling
Purposive sampling is a type of nonprobability sampling in which the researcher selects the sample from the population based on specific criteria. This type of sampling is typically used when the researcher needs to study a population with specific characteristics. The main advantage of purposive sampling is that it allows the researcher to study a population of particular interest. However, it is vulnerable to selection bias, as the sample may not be representative of the population.
Quota Sampling
Quota sampling is a type of nonprobability sampling in which the researcher selects the sample from the population based on predetermined criteria. This type of sampling is typically used when the researcher wants to ensure that the sample is representative of the population. The main advantage of quota sampling is that it allows the researcher to obtain a representative sample. However, it is vulnerable to selection bias, as the sample may not be selected randomly.
Snowball Sampling
Snowball sampling is a type of nonprobability sampling in which the researcher selects the sample from the population based on referrals. This type of sampling is typically used when the researcher needs to study a population that is difficult to access. The main advantage of snowball sampling is that it can be used to access hard-to-reach populations. However, it is vulnerable to selection bias, as the sample may not be representative of the population.
Advantages and Disadvantages of Nonprobability Sampling
The main advantages of nonprobability sampling are that it is relatively inexpensive and easy to implement, and that it allows the researcher to study a population of particular interest. However, nonprobability sampling is also vulnerable to selection bias, as the sample may not be representative of the population.
Application in Research
Nonprobability sampling is commonly used in research, particularly in fields such as sociology, psychology, and marketing. For example, convenience sampling is often used in surveys and questionnaires, purposive sampling is often used in qualitative research, quota sampling is often used in opinion polls, and snowball sampling is often used in studies of hard-to-reach populations.
Conclusion
Nonprobability sampling is a type of sampling method in which the sample elements are not selected on the basis of randomness, and therefore, the samples are not considered representative of the population. This article has provided an overview of the different types of nonprobability sampling, their advantages and disadvantages, and their application in research.
References
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