It is for this reason that some form of sampling is generally carried out, and one of the most popular sampling methods is a process known as purposive sampling. So, what is purposive sampling and why would you use it? Simply put, purposive sampling is when a researcher chooses specific people within the population to use for a particular study or research project. Unlike random studies, which deliberately include a diverse cross section of ages, backgrounds and cultures, the idea behind purposive sampling is to concentrate on people with particular characteristics who will better be able to assist with the relevant research.
For example, if you are researching workplace packages that include dental benefits, then, logically, you would not include people who are unemployed or who have not been offered a benefits package by their place of work; they would be unable to relate anything relevant to your study. Rather, you would focus on people who were employed and who had dental included in their workplace benefits package. Wide range of techniques.
Since there are several different types of purposive sampling e. This variety will, in turn, give you a better cross-section of information.
Qualitative research usually involves a number of different phases, with each phase building progressively onwards from the original. This being the case, purposive sampling is useful to a researcher because they can use the variety of methods available to build and increase their research data.
For example, you could start with critical case sampling, and then using the information gathered, progress to expert sampling in stage two. The main disadvantage of purposive sampling is the high probability of researcher bias, as each sample is based entirely on the judgment of the researcher in question, who generally is trying to prove a specific point.
For this reason, researchers need to strive to make decisions based on accepted criteria, not on what will best support their theory. When a researcher publishes their findings, they need to be able to successfully defend their proposal from critics. Information on whether or not drugs are used appropriately can be obtained from the focused illness recalls.
By conducting semi-structured interviews with both groups and comparing findings you can get an idea of the reasons for appropriate and inappropriate practices. The main decision you need to take when planning focus group discussions is what focus you intend to have, and how many FGDs you intend to hold. Decide which population sub-groups need to be interviewed. Limit the scope of the study to those sub-groups which have direct experience with the problem. Usually local leaders are asked to select respondents for the focus groups.
Aim for around participants per group; and conduct at least two FGDs per population group involved. So, for example, two with men and two with women, or two with adults and two with adolescents.
If the conclusions of the two groups are not in agreement you may need to hold a third FGD to further investigate the issues. Convenience sampling Convenience sampling is a method in which, for convenience sake, the study units that happen to be available at the time of data collection are selected in the sample.
Maximum variation sampling This sampling method aims to select study units which represent a wide range of variation in dimensions of interest. Snowball sampling Snowball sampling is perhaps the most common sampling method used in qualitative studies. Sampling contrasting cases Comparative studies sampling will involve two or more population groups with distinct characteristics.
Qualitative sampling respondents for semi-structured interviews and FGDs The qualitative methods presented in Chapter 3 for investigation on drug use include semi-structured interviews and FGDs. Sampling for semi-structured interviews First you need to define whom you want to interview. Sampling for focus group discussions The main decision you need to take when planning focus group discussions is what focus you intend to have, and how many FGDs you intend to hold.
Why study medicines use by consumers. What influences medicines use by consumers. How to study medicines use in communities. Prioritizing and analysing community medicines use problems. Monitoring and evaluating rational medicines use interventions in the community. Another major advantage of this type of sampling is the wide range of sampling techniques that researchers can use across different qualitative research designs.
Typically, qualitative research designs involve multiple phases and require different types of sampling techniques at every phase. Purposive sampling becomes useful in this situation, because it offers a wide selection of non-probability sampling techniques. For example, a researcher can use critical case sampling to determine if a phenomenon is worth investigating further.
Then, he can use expert sampling to examine specific issues. What Are the Advantages of Purposive Sampling? Quick Answer The main advantage of purposive sampling is that a researcher can reach a targeted sample quickly. What Are the Advantages of Probability Sampling? Full Answer Purposive sampling saves time, money and effort.
Purposeful sampling is widely used in qualitative research for the identification and selection of information-rich cases related to the phenomenon of interest. Although there are several different purposeful sampling strategies, criterion sampling appears to be .
Critical case sampling is a type of purposive sampling technique that is particularly useful in exploratory qualitative research, research with limited resources, as well as research where a single case (or small number of cases) can be decisive in explaining the phenomenon of interest.
Alternatively, purposive sampling method may prove to be effective when only limited numbers of people can serve as primary data sources due to the nature of research design and aims and objectives. Qualitative data analysis; Quantitative data analysis; Writing and disseminating research; Browse Discipline. Explore the research methods terrain, Purposive Sampling | The SAGE Dictionary of Social Research Methods Search form. Not Found.
Purposive Sampling generalizable or the existence of a particular kind of case will undermine all that you 'know' to be true about a phenomenon, then look for that kind of case.". Purposeful sampling for qualitative studies There are several strategies for purposeful sampling of information-rich cases. The methods most commonly used in qualitative studies are given here, including the purpose for which the method is especially useful and its disadvantages.