However, where it is not possible to use probability sampling, non-probability sampling at least provides a viable alternative that can be used. Therefore, we choose to study just a sample of these Facebook users. This is bad from two perspectives, but only one is arguably a potential ethical issue: Sampling strategy The sampling strategy that you select in your dissertation should naturally flow from your chosen research design and research methods , as well as taking into account issues of research ethics. For example, I might decide that her sampling frame is every student at the university where I study.

Broadly speaking, there are two groups of sampling technique: Data analysis techniques , make sure that you have taken into account: Hence, despite having some limitations, purposive sampling is the only possible solution when some of the units are very important cannot be missed out. To learn more about other purposive sampling techniques , see the article: For example, critical case sampling may be used to investigate whether a phenomenon is worth investigating further, before adopting an expert sampling approach to examine specific issues further. If you are considering whether to use non-probability sampling, it is important to consider how your choice of research strategy will influence whether this is an appropriate decision.

Some examples of each of these types of population are present below:.


Practical reasons Non-probability sampling is often used because the procedures used to select units for inclusion in a sample are much easierquicker and cheaper when compared with probability sampling.

Notice that a sampling frame is not as large as the population, but it’s still a pretty big group of people.

laerd dissertation purposive sampling

This is not just a duty to yourself or the sponsors of your dissertation if you have anybut more importantly, to the people that take part in your research i. Comparison of Convenience Sampling and Purposive Sampling. Specify a sampling frame9 7 C. Not an ethical issue Let’s take the example of the career choices of students at your university. This would help you to avoid a potentially more time consuming and expensive piece of research looking into a potential problem or issue that actually doesn’t exist.


Finally, researchers sometimes refer to populations consisting of data or pieces of data instead of units or cases. Maximum variation sampling Homogeneous sampling Typical case sampling Extreme or deviant case sampling Critical case sampling Total population sampling Expert sampling.

In sampling dissertation qualitative research laerd purposive

What is total population sampling? A researcher may have a specific group in mind, such as high eampling business executives. Some examples of each of purpoisve types of population are present below: The word typical does not mean that laetd sample is representative in the sense of probability sampling i. To learn more about other purposive sampling techniquessee the article: Collectively, these units form the sample that the researcher studies [see our article, Sampling: It starts with a purpose in mind and the sample is thus selected to include people of interest and exclude those who purposivd not suit the purpose.

Whilst such critical cases should not be used to make statistical generalisations, it can be argued that they can help in making logical generalisations.

This is a potential ethical issue. Principles of non-probability sampling There are theoretical and practical reasons for using non-probability sampling. In this example above, the population consisted of people with a rare disease, but there are many types of uncommon characteristic.

It is this decisive aspect of critical case sampling that is arguably the most important.

laerd dissertation purposive sampling

Non-probability sampling techniques refer on the subjective judgement of the researcher when selecting units from the population to be included in the sample. If you are new to sampling, there are a number of key terms and basic principles that act as a foundation to the subject. Despite this, lard would expect that the likelihood of this happening is fairly low.


Rather, it is a choice, the purpose of which varies depending on the type of purposing sampling technique that is used.

When selecting units from the population to be included in your sample, it is sometimes desirable to get hold of a list of the population from which you select units.

The basic principle behind maximum variation sampling is to gain greater insights into a phenomenon by looking at it from all angles. Overall, the types of non-probability sampling technique you are likely to come across include quota samplingpurposive samplinglaerv samplingsnowball sampling and self-section sampling.

In sampling dissertation qualitative research laerd purposive

A core characteristic of non-probability sampling techniques is that samples are selected based on the subjective judgement of the researcher, rather than random selection i. Example 3 The knowledge gains from managers that have didsertation on long-term international assignments in a Fortune company.

Achieving the goals of such qualitative research designs requires different types of sampling strategy and sampling technique.

Units As discussed above, the population that you are interested consists of unitswhich can be peoplecases or pieces of data.

This article discusses the pufposive of non-probability sampling and briefly sets out the types of non-probability sampling technique discussed in detail in other articles within this site. Qualitative research designs can involve multiple phases, with each phase building on the previous one.

Of the more than schools that converted, only 7 were primary schools i.