|
Purposive sampling and Convenience sampling, methods are crucial in research for selecting a representative subset of a population. Purposive samples and Convenient samples are two main categories of non-probability samples.
The purpose of this article is therefore to assist the reader in understanding the key differences between these two approaches.
What is Purposive Sampling?
Purposive sampling is also known as judgmental or selective sampling and is categorized as the non-probability sampling technique. Where the participants are chosen by the researcher. This method is purposive, this is because the researcher is fully responsible for selecting the right people whose results are likely to be found.
Purpose sampling is used in qualitative methods of research in a bid to gain a maximum understanding of the phenomena under study as opposed to the general total population of individuals under study.
Characteristics of Purposive Sampling
The characteristics of Purposive Sampling are as follows:
- Purpose-Driven Selection: Researchers select participants based on specific characteristics or criteria relevant to the study’s objectives.
- Expert Judgment: The researcher uses their expertise and knowledge to identify and choose individuals who are most likely to contribute valuable data.
- Focus on Depth: This method aims to obtain in-depth insights and a comprehensive understanding of the research topic.
- Non-Random Sampling: Participants are not chosen randomly; the selection is intentional and strategic.
- Flexibility: Researchers can adjust the selection criteria as the study progresses to include additional relevant participants.
What is Convenience Sampling?
Convenience sampling is one of the subcategories of non-probability sampling where subjects are chosen depending on their easiness of access.
This method derives its strength from the participants because the latter are easy to locate by the researcher in case they agree to participate. Convenience sampling is used often in exploratory research, pilot studies or when time and/or money is an issue.
Characteristics of Convenience Sampling
The characteristics of Convenience Sampling are as follows:
- Ease of Access: In this study, it is emphasized that participants must be conveniently available, and preferably close to the researcher.
- Quick and Cost-Effective: However, it is often employed where there is limited time or where the amount of money available for the research work is limited since this method is relatively fast and cheap.
- Lack of Representativeness: The sample may not accurately represent the broader population, leading to potential biases.
- Non-Random Selection: Participants are chosen based on convenience rather than random sampling techniques.
- Useful for Preliminary Research: Even though convenience sampling is not regarded as the best way of sampling, many primary research studies use it to get initial information.
Difference between Purposive and Convenience Sampling
The difference between Purposive and Convenience Sampling are as follows:
|
Criteria
|
Purposive Sampling
|
Convenience Sampling
|
|
Selection Process
|
Based on specific characteristics and criteria
|
Based on ease of access and proximity
|
|
Researcher Control
|
High
|
Low
|
|
Potential for Bias
|
Medium (due to subjective selection)
|
High (due to non-representative sample)
|
|
Typical Use Cases
|
Qualitative research, case studies
|
Exploratory research, pilot studies
|
|
Flexibility
|
High
|
High
|
|
Representativeness
|
Potentially higher if criteria are well-defined
|
Generally low
|
|
Time and Cost Efficiency
|
Moderate
|
High
|
Advantages and Disadvantages of Purposive and Convenience Sampling
By appreciating the strengths and weaknesses of the purposive and convenience sampling technique, one is in a position to make the right decision when it comes to the most appropriate research sample technique to undertake their research depending on the available resources and the nature of research.
For Purposive Sampling
Advantages Purposive Sampling are:
- Relevance and Depth: Ensures that the selected participants are highly relevant to the research topic, providing in-depth and detailed data.
- Efficient Use of Resources: Focuses resources on a targeted group, which can lead to more meaningful insights with fewer participants.
Disadvantages Purposive Sampling are:
- Subjectivity and Bias: The selection process is subjective, which can introduce researcher bias and affect the validity of the results.
- Limited Generalizability: It is crucial to emphasize that the conclusions may only apply to the sampled groups of patients and cannot be considered representative of the entire population.
- Time-Consuming: Conducting the participant identification and selection process to obtain only the right subject can be quite time-consuming.
For Convenience Sampling
Advantages Convenience Sampling are:
- Speed and Simplicity: Very convenient to apply because it can be done in a short time and is suitable to use in case you need results in a short period of time, for example, for a pilot study.
- Cost-Effective: Requires fewer resources, making it a budget-friendly option for researchers.
- Practicality: Useful in situations where access to a larger, random sample is not feasible.
Disadvantages Convenience Sampling are:
- High Potential for Bias: The sample may not be representative of the larger population, leading to biased results.
- Limited Validity: Findings may lack validity and reliability due to the non-random and potentially biased selection process.
- Lower Credibility: Research findings based on convenience sampling may be viewed as less credible by the academic community.
Conclusion
Comparing purposive and convenience sampling is significant and necessary for every researcher when choosing the most suitable tool for investigations. Purposive sampling enables one to choose participants with rich information hence enhancing the depth of information and convenience sampling enables one to get generalizable data within a short span and at a lesser cost. Each of the two methods has its strengths and weaknesses and thus their application depends on the research context and aims. The selection of an appropriate method of sampling can help improve the credibility and dependability of the results obtained, and hence, assist in promoting the creation of better qualitative research studies.
Related Article:
FAQs on Purposive and Convenience Sampling
Why is purposive sampling better than convenience sampling?
Purposive sampling is more appropriate because it involves the deliberate identification of people with the desired characteristics that yield accurate and insightful information.
Can convenience sampling be random?
No, convenience sampling is not random. It selects participants based on ease of access, not random selection.
Can purposive sampling be generalized?
Thus, purposive sampling results can never be generalized to the entire population since the technique is employed to concentrate on an individual segment.
Is convenience sampling biased or unbiased?
Convenience sampling is often considered biased because the method does not encompass all the individuals in the population.
What is a good sample size for purposive sampling?
The sample size for purposive sampling is relative, yet it depends on the study’s objective and ranges from 10 to 30 participants.
|
