Non-probability Sampling
Introduction
Non-probability sampling is a statistical sampling technique where the samples are gathered in a process that does not give all the individuals in the population equal chances of being selected. This method is often used where the population is vast and it is difficult to identify every individual in the population.
Types of Non-Probability Sampling
There are several types of non-probability sampling methods, each with its own set of strengths and weaknesses.
Convenience Sampling
Convenience sampling is a type of non-probability sampling method where the first available primary data source will be used for the research without additional requirements. In other words, this sampling method involves getting participants wherever you can find them and typically wherever is convenient.
Judgmental or Purposive Sampling
Judgmental sampling or purposive sampling is a type of non-probability sampling technique where the researcher selects the units of the population that he/she thinks would be most beneficial or representative of the population under study. The researcher uses their judgment to select participants.
Quota Sampling
Quota sampling is a non-probability sampling technique wherein the assembled sample has the same proportions of individuals as the entire population with respect to known characteristics, traits, or focused phenomenon.
Snowball Sampling
Snowball sampling is a non-probability sampling technique that is used by researchers to identify potential subjects in studies where subjects are hard to locate.
Advantages and Disadvantages of Non-Probability Sampling
Non-probability sampling methods offer a range of advantages and disadvantages, largely dependent on the sampling technique used.
Advantages
Non-probability sampling can be a valuable tool in research where the population is large and difficult to measure. It allows for the collection of useful data and information that can be used to draw conclusions and make decisions.
Disadvantages
The main disadvantage of non-probability sampling is that it can lead to the selection of a biased sample, one that does not accurately represent the population. This can lead to skewed results and inaccurate conclusions.
Applications of Non-Probability Sampling
Non-probability sampling methods are widely used in many areas of research, including social sciences, market research, and others. They can be particularly useful in exploratory research where the goal is to get an idea about a topic rather than make precise estimates.
Conclusion
Non-probability sampling is a widely used method of selecting a sample from a population. It is often used when the population is large, and it is impractical or impossible to identify every member of the population. While it has its advantages, it also has its disadvantages, including the potential for bias and the inability to generalize results to the larger population.