Presentation on theme: "Qualitative research methodology"— Presentation transcript:
1 Qualitative research methodology Paper IIIQualitative research methodology
2 Discuss sampling techniques appropriate to qualitative research. Objective 1.5Discuss sampling techniques appropriate to qualitative research.
3 Sampling in Qualitative Research Sampling in Qualitative Research We will discuss three of the most common sampling methods used in qualitative research: 1. Purposive sampling 2. Snowball sampling.Sampling in Qualitative Research
4 What is purposive sampling? As defined by Kerlinger (1986), purposive sampling is another non-probability based sampling.It is characterized by a deliberate effort to obtain representative samples through the inclusion of groups or typical areas in a sample.What is purposive sampling?
5 What is purposive sampling? The researcher actively selects the most productive sample to answer the research question.This can involve developing a framework of the variables that might influence an individual's contribution and will be based on the researcher's practical knowledge of the research area, the available literature and evidence from the study itself.What is purposive sampling?
6 What is purposive sampling? Purposive sample sizes are often determined on the basis of theoretical saturation (the point in data collection when new data no longer bring additional insights to the research questions).Purposive sampling is therefore most successful when data review and analysis are done in conjunction with data collection.What is purposive sampling?
7 When to use purposive sampling? Purposive sampling design is usually used when a limited number of individuals possess the trait of interest.It is the only viable sampling technique in obtaining information from a very specific group of people.When to use purposive sampling?
8 When to use purposive sampling? It is also possible to use purposive sampling if the researcher knows a reliable professional or authority that he thinks is capable of assembling a representative sample (this is a very subjective sample technique).The purposive sampling technique essentially is dependent upon the skill of the researcher to identify and find specific participants.When to use purposive sampling?
9 What is purposive sampling? In essence, subjects are selected because of some characteristic. Patton (1990) has proposed the following cases of purposive sampling:Typical Case - Illustrates or highlights what is typical, normal, average.Extreme or Deviant Case - Learning from highly unusual manifestations of the phenomenon of interest, such as outstanding success/notable failures, top of the class/dropouts, exotic events, crises.Convenience - Saves time, money, and effort. Poorest rational; lowest credibility. Yields information-poor cases.What is purposive sampling?
10 purposive sampling Advantages of Those who are unsuitable for the sampling study or who do not fit the bill have already been eliminated, so only the most suitable candidates remain.As the most appropriate people for the study have been selected, this process becomes a lot less time consuming.purposive samplingAdvantages of
11 purposive sampling Advantages of The results of purposeful sampling are usually expected to be more representative of the population than those achieved with an alternative form of sampling.If you are looking for a very rare or much sought after group of people for a particular research study, using purposive sampling may usually be the only way you can track them down.purposive samplingAdvantages of
12 purposive sampling Advantages of Quite often market researchers use this type of sampling in order to target a particular group of people.Basing their results on what this group has said, their findings will then be used as a representation of the rest of the population.Deciding in advance what group to target based on the types of results a company is expecting to find will help them save costs and get the job done as soon as possible.purposive samplingAdvantages of
13 purposive sampling Limitations of Quite often market researchers use this type of sampling in order to target a particular group of people.Basing their results on what this group has said, their findings will then be used as a representation of the rest of the population.Deciding in advance what group to target based on the types of results a company is expecting to find will help them save costs and get the job done as soon as possible.purposive samplingLimitations of
14 purposive sampling Limitations of The selection criteria the researcher uses can be very arbitrary and are almost always subjective.The narrowness of the questions used will reflect the researcher's particular stance on a subject far more than a random sample.purposive samplingLimitations of
15 purposive sampling Limitations of The sample population used may not necessarily be entirely the population that the researcher is trying to reach.As such, since such a small sample population is often used, a small variation in the sample will cause deviance in the results.purposive samplingLimitations of
16 Snowball sampling is a non-probability sampling technique that is used by researchers to identify potential subjects in studies where subjects are hard to locate.This type of sampling technique works like chain referral. After observing the initial subject, the researcher asks for assistance from the subject to help identify people with a similar trait of interest.Snowball sampling
17 The process of snowball sampling is much like asking your subjects to nominate another person with the same trait as your next subject.The researcher then observes the nominated subjects and continues in the same way until the obtaining sufficient number of subjects.The snowball sampling technique essentially is dependent upon the participants to identify and find specific participants.Snowball sampling
18 The process of snowball sampling is much like asking your subjects to nominate another person with the same trait as your next subject.The researcher then observes the nominated subjects and continues in the same way until the obtaining sufficient number of subjects.The snowball sampling technique essentially is dependent upon the participants to identify and find specific participants.Snowball sampling
19 When can this type of sampling be useful? Snowball samplingWhen can this type of sampling be useful?
20 Application of Snowball sampling If obtaining subjects for a study that wants to observe a rare disease, the researcher may opt to use snowball sampling since it will be difficult to obtain subjects.It is also possible that the patients with the same disease have a support group; being able to observe one of the members as your initial subject will then lead you to more subjects for the study.Snowball sampling is often used with focus groups in qualitative research methods.Application ofSnowball sampling
21 Advantages of snowball technique… The chain referral process allows the researcher to reach populations that are difficult to sample when using other sampling methods.The process is cheap, simple and cost-efficient.This sampling technique needs little planning compared to other sampling techniques.
22 Limitations of snowball technique… Representativeness of the sample is not guaranteed. The researcher has no idea of the true distribution of the population and of the sample.Sampling bias is also a fear of researchers when using this sampling technique.Initial subjects tend to nominate people that they know well. Because of this, it is highly possible that the subjects share the same traits and characteristics, thus, it is possible that the sample that the researcher will obtain is only a small subgroup of the entire population.