Comprehensive Guide on Different Sampling Methods in Social Research

     1. Quota sampling

Quota sampling uses “control characteristics” to categories a target population into multiple subpopulations with shared characteristics. After these subgroups are defined, the researcher chooses elements from each subgroup using non-probability sampling techniques such as convenience or judgment. This method of sampling is similar to stratified random sampling as both these methods divide the population into subgroups based on certain variables. However, the main difference between the two is that in stratified random sampling SRS is used to select elements from the subgroups whereas in quota sampling, judgment or convenience is used instead. 

For example, if the participation of respondents from every city in Canada is critical to a study, then the researcher must group participants city wise and choose elements from each of these subpopulations using convenience or judgment. 

     2. Snowball sampling

Snowball sampling is a method of non-probability sampling where the researcher uses their initial group of participants to help create and identify a larger network of those who qualify to be a part of the target population. This method of sampling is often used when the target population of a study is really small, hard to find, and/or inaccessible. 

For example, in a study about homeless people, a researcher may ask homeless people that are readily available to them to give a list of areas where more homeless people can be found. In this case, the researcher is using one element, or a few elements, of the target population as a resource to access more people in that population.

     3. Judgmental sampling

Judgmental sampling, also known as purposive sampling, is a quick, low-cost method of non-probability sampling. In this method, the researcher uses their judgment, logic, and expertise to select participants to be a part of the sample. 

For example, if a survey’s target population is marketing experts, then a researcher may choose to interview any marketing experts they come across. 

     4. Convenience Sampling

Convenience sampling, also known as accidental sampling, is a non-probability sampling process carried out at a researcher’s convenience. This means that the researcher chooses respondents whenever and wherever they are met. This method of sampling is used when there is a limitation of time or if certain elements of the population are not easily come across.

For example, if I want to study the buying behaviors of sporting good customers, I may visit different sporting good stores in my city in order to survey different customers at these stores. These customers will be a part of my sample group.