• July 7, 2019

Also known as judgmental, selective or subjective sampling, purposive sampling relies on the judgement of the researcher when it comes to selecting the units e. The basics Probability sampling Simple random sampling Systematic random sampling Stratified random sampling Non-probability sampling Quota sampling Self-selection sampling Convenience sampling Snowball sampling Purposive sampling. There are five types of non-probability sampling technique that you may use when doing a dissertation at the undergraduate and master’s level: Whilst you don’t want to be wasting peoples’ time, and should try and avoid doing so, this is not a major ethical issue. In other words, it can be difficult to convince the reader that the judgement you used to select units to study was appropriate.

In such instances, different types of sampling technique may be required at each phase. Rather than a comprehensive look at sampling, the article presents the sampling basics that you would need to know if you were an undergraduate or master’s level student about to perform a dissertation or similar piece of research. The word population is different when used in research compared with the way we think about a population under normal circumstances. In such cases, it is often more appropriate to refer to each of these e. In the example above, the sample size selected may be just or of the Facebook users that are part of our population of frequent, male, Facebook users in the United States.

Alternately, the particular expertise that is being investigated may form the basis of your research, requiring a focus only on individuals with such specific expertise.

Sample When we are interested in a population, it is often impractical and sometimes undesirable to try and study the entire population.

In sampling dissertation qualitative research laerd purposive

We explain the different goals of these types of purposive sampling technique in the next section. Therefore, you need to check that you have the right to access the list in the first place.


laerd dissertation purposive sampling

In this example above, the population consisted of people with a rare disease, but there are many types of uncommon characteristic. By contrast, critical case sampling is frequently used in exploratoryqualitative research in order to assess whether the phenomenon lared interest even exists amongst other reasons.

Let’s look where this may or may not be a problem:.

Sampling techniques, sample size and other factors affecting your dissertation | Lærd Dissertation

However, where it is not possible to use probability sampling, non-probability sampling at least provides a viable alternative that can be used. The important point is that you do not want to expose individuals to distress or harm unnecessarily.

Collectively, these units form the sample that the researcher studies [see our article, Sampling: These are discussed in turn below: This is the case when using certain types of sampling technique i. Despite this, for researchers following a quantitative research designnon-probability sampling techniques can often be viewed as an inferior alternative to probability sampling techniques.

In sampling dissertation qualitative research laerd purposive

The sampling frame is very similar to the population you are studying, and may be exactly the same. Customer transactions at Wal-Mart or Tesco between two time points e. Specify a sampling method10 There are basically two ways to choose a sample from a sampling frame: Specify a sampling frame9 7 C. By conditionswe mean the units i. Since purposive sampling is just one type of non-probability samplingsee the article: Examples of total population sampling The examples of total population sampling below attempt to highlight two of the characteristics of total population samples, discussed above: The key component is that research subjects or organisations volunteer to take part in the research rather than being approached by the researcher directly.

As a researcher, even when you’re an undergraduate or master’s level student, you have a duty not to expose an excessive number of people to unnecessary distress or harm.


Non-probability sampling techniques refer on the subjective judgement of the researcher when selecting units from the population to be included in the sample. Principles of non-probability sampling Types of non-probability sampling. Total population sampling23 Total population sampling is a type of smapling sampling technique where you choose to examine the entire population i.

Achieving the goals of such qualitative research designs requires different types of sampling strategy and sampling technique. Not an ethical issue Let’s take the uprposive of the career choices of students at your university.

laerd dissertation purposive sampling

Purposive sampling Purposive sampling, also known as judgmentalselective or subjective sampling, is a type of non-probability sampling technique. The article is divided into two sections: Non-probability sampling focuses on sampling techniques where the units that are investigated are based on the judgement of the researcher [see our articles: However, since you may find other textbooks referring to these units as people, cases, or pieces of data, we have provided some further clarification below:.

Therefore, expert sampling is a cornerstone purposivee a research design known as expert elicitation.

Rather, the word typical means that the researcher has the ability to compare the findings from a study using typical case sampling with other similar samples i. The important point is that you fail to answer your research questions not because a potential answer did not exist, but because your sample size was too small for such an answer to be discovered or interpreted. Identify the population of interest8 A population is the group of people that you want to make assumptions about.

Stratified random Sampling d.