Selecting your sample
The sample is the set of individuals you focus on in your research. The data you collect from your sample then needs to be considered in relation to the rest of the target population with regard to how representative your findings are of that population. The target population describes individuals in a particular set of related contexts e.g. primary schools or a group of individuals linked by a common characteristic e.g. early years practitioners.
Probability sampling
When carrying out probability sampling the aim is that all elements of the sample have an equal probability of being selected and therefore the findings of your research are likely to be representative of the sample. This form of sampling is usually associated with large scale studies. An example of probability sampling is systematic sampling, which is a way of achieving similar findings to using a much larger random sample.
Non-probability or purposive sampling
In this approach to sampling you would not aim for a sample that is representative of the population. Purposive sampling is used for a particular purpose e.g. to study an issue in a particular school and the findings of your research could not be generalised to the rest of the population. One of the most common forms of sampling in practitioner research is case study, where the study draws on a small sample from a particular context such as a school. Although findings from a case study cannot be generalised to the population, they can be used to identify particular themes within a particular research focus which may have relevance to the wider population or to illustrate what can be achieved in practice (for example through action research) (adapted from Newby, 2014).
Further reading:
Checklist
The following checklist will help you to identify the different stages you need to consider when constructing your research design (adapted from Newby, 2014):
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Use your own observations and reading to help you identify a research focus.
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Develop a specific research question, purpose statement, or hypothesis
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Develop a model to represent factors (variables) impacting on the outcomes which you are interested in researching.
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Consider what data you need to collect and the most appropriate approach to enable you to achieve this.
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Think carefully about the size and composition of the sample and the ethical issues that need to be addressed, especially with regard to safeguarding and other risks
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Identify methods and research instruments that will enable the research question to be answered or the hypothesis to be tested.
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Identify the approaches you will use to process and analyse your data and consider how the data needs to be presented to enable you to provide convincing evidence.
