However, the use of this sampling technique is discouraged by many dissertation supervisors due to inability to generalise research findings, along with other disadvantages mentioned further below. If you analyze the results of a convenience survey by list source, you will often find dramatic differences in the answers from the different lists, often in ways that confound easy explanation. A convenience sample is simply one where the units that are selected for inclusion in the sample are the easiest to access. In total population sampling, researchers choose to study the entire population because the size of the population that has the particular set of characteristics that we are interest in is typically very small. The word population is different when used in research compared with the way we think about a population under normal circumstances.
Here, snowball sampling , a type of non-probability sampling technique, provides a solution. In addition, you need to decide whether non-probability sampling is appropriate based on the research strategy you have chosen to guide your dissertation. While quota sampling improves the representation of specific strata within the sample, it also ensures no overrepresentation. In our example of the 10, university students, we were only interested in achieving a sample size of students who would take part in our research. Convenience sampling is a type of non-probability sampling technique. In order to select a sample n of students from this population of 10, students, we could choose to use quota sampling , convenience sampling , purposive sampling , self-selection sampling and snowball sampling:.
Laerv sampling is perhaps the most common of all sampling techniques which is because it is the easiest to perform. The convenience sample often suffers from biases from a number of biases. Non-random error results from bias being introduced into the sample from some flaw in the design or implementation of the sample.
Fourth, how is the population distributed on the variable of interest? The professor teaches a sociology class to mostly college freshmen and decides to use his or her class as the study sample.
We discuss sampling techniques further next.
A potential ethical issue Imagine that you were interested in the effect of a carbohydrate free diet on the concentration levels of female university students in the classroom. Since the dissettation of convenience sampling is easy access, we may simply choose to stand at one of the main entrances to campus of the University of Bath where it would be easy to invite the many students that pass by to take part in the research.
In both cases, a convenience sample can lead to the under-representation or over-representation of particular groups within the sample. Otherwise the same process would get more time consuming and expensive.
The sampling frame is very similar to the population you are studying, and may be exactly the same. This is in stark contrast to probability sampling techniqueswhere the selection of units is made randomly.
Non-probability sampling | Lærd Dissertation
These units can be people, cases e. Convenience sampling explained Advantages of convenience sampling Disadvantages limitations of convenience sampling. Whether you are using a probability sampling or non-probability sampling technique to help you create your sample, you will need to disseryation how large your sample should be i.
A convenience sample is simply one where the units that are selected for inclusion in the sample are the easiest to access.
Non Probability sampling & its types
Non-probability sampling techniques refer on the subjective judgement of the researcher when selecting units from the population to be included in the sample. Systematic bias stems from sampling bias. In convenience sampling no inclusion criteria identified prior to selection of subjects. As such, we would continue to invite students to take part in the research until our sample size was reached.
This means you select dorm room 3 as your first room, dissertatiion then every fourth room down the list 3, 7, 11, 15, 19, etc.
A sample is over-sized when there are more units e. This article explains a what convenience dissertagion is and b the advantages and disadvantages limitations of convenience sampling.
Convenience sampling | Lærd Dissertation
However, the use of this sampling technique is discouraged by many dissertation supervisors due to inability to generalise research findings, along with other disadvantages mentioned further below. Say your student body of 10, students is made up of 8, – West; samplinb, – East; – Midwest; – South; – Foreign.
This can lead to your sample being unrepresentative of convenidnce population you are interested in. When thinking about the population you are interested in studying, it is important to be precise.
At the end of the day, when it comes to sample size, you need to decide what it laedr more important to you, certainty or precision, and what your tolerance for risk is, especially if your market research budget is small. Have the results been replicated with different samples and data collection methods?
Where this happens, it raises ethical issues because the picture being built through the research can be excessively narrow, and arguably, unethically narrow. The selection of each unit is independent of the selection of every other unit. However, the manager has managed to secure permission for sxmpling to spend two days in the organisation to collect as many survey responses as possible. However, if the population you were interested in was more specificyou should make this clear.
Did others take part out of kindness or because they had a particular grievance with the organisation?
When thinking about the impact of sampling strategies on research ethics, you need to take into account: Subjects are selected on the basis of ease of recruitment in convenience sampling.