S.TRUEMAN PhD THESIS 2016

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and statistics collected together for reference or analysis’ ( Shorter Oxford Dictionary , 2007) and may consist of numbers, words, or images, particularly as measurements or observations of a set of variables’. Hence ‘data’ are the smallest entities or ‘recorded elements resulting from some experience, observation, experiment, or other similar situation’ (Yin, 2011, p. 130). The impressions of a researcher are derived from their use of, and engagement with, multiple types and sources of data (Stake, 1995; Yin, 1994, 2003). The use of multiple types and sources of information along converging lines of inquiry is critical to the trustworthiness and credibility of the inquiry when compared with a single source of information. Traditional types of data include documentation, archival records, interviews, direct observation, participant observation and physical artefacts. A case study’s strength is ‘its ability to deal with a full variety of evidence—documents, artefacts, interviews, and observations’ (Yin, 2003a, p. 8). The choice of data sources depends on a number of factors such as the phenomena under investigation, access to information, and the skills of the researcher. It is not critical for a case study to make use of most or all of the different types of data. Each type of data has its strengths and weaknesses, and no single type of data has a complete advantage over another. Ideally, data types should complement one another (Denzin & Lincoln, 2005; Stake, 1995). Hence the researcher used a combination of participant interviews, policy documents, research reports and publications, self-knowledge and reflection, observation through embeddedness in the field, historical and pictorial artefacts. This approach is consistent with Creswell (2007) who states, ‘. . . the investigator explores a bounded system (a case) … over time, through detailed, in-depth data collection