Validity and reliability

Validity varies in quantitative and qualitative research, but in both methods, it tests the quality of data and results (Creswell & Piano Clark, 2007:133). Mustafa (2011:27) considers validity to be a tool for determining whether research measures what it was intended to measure, or how truthful the results are. Reliability determines whether the study can be reproduced using a similar methodology. Reliability is defined differently between positivists, constructionists and critical researchers, but there is agreement about the need for trustworthiness, accuracy and dependability of research findings (Lewis, 2009:7).

Maxwell (1992:285) identifies five categories of validity: descriptive, interpretive, theoretical, generalisable and evaluative validity. In my research, I employed the first two categories. Descriptive validity was achieved through audio recording and transcribing of the interviews

. This provided an accurate record of what participants expressed. Interpretive validity was achieved through seeking to understand information from the perspective of the participants in their contexts. Interpretations were verified through member checks.

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The credibility of data was further validated through the following strategies as discussed by Merriam (2009:229).

3.6.1 Piloting the instruments

As posited by Postlethwaite (2005:20), pilot studies are conducted for two main purposes: first, to assess whether the instrument has been designed in a manner that will elicit required information from respondents; second, to determine whether questions are pitched at the appropriate level. Piloting the instruments assisted me in detecting flaws or weaknesses within the design.

The teacher questionnaire (Appendix 6), the teacher interview schedule (Appendix 7) and the subject adviser interview schedule (Appendix 8) were administered for piloting purposes. The teacher questionnaire was administered to five teachers from a district that was not one of the districts sampled. The teacher interview was conducted with one of the teachers who piloted the questionnaire and the subject adviser interview was conducted with the subject adviser of the same district. During the piloting process, a number of flaws were detected concerning the instruments. In the teacher questionnaire these included duplication of questions, unclear questions in the questionnaire and illogical sequencing of questions. After the interview with the teacher and subject adviser, they participated in a discussion about how they experienced the interview and the questions that were asked. This proved most helpful, as they were able to share how they felt the interview could be enhanced. Their inputs improved interview schedules. They felt that they would have liked to have access to the questions a day or two beforehand to internalise and think about the questions. Their advice was heeded and the interview schedule was e-mailed to respondents beforehand.

3.6.2 Triangulation

Triangulation is a powerful strategy for enriching the quality, especially credibility, of a research study (Krefting, 1991:219). ‘Triangulation refers to the designed use of multiple methods, with offsetting or counteracting biases, in investigations of the

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same phenomenon in order to strengthen the validity of inquiry results’ (Greene, Caracelli & Graham, 1989:256).

In this study, methodological triangulation was used: both qualitative and quantitative methods were engaged. Triangulation was employed in the use of different respondents: teachers and subject advisers.

3.6.3 Member checks

Brenner (2006:368) argues that it is useful to check researcher’s interpretation of meaning against participants’ perceptions in a process called member checking. This strategy of comparing research data with participants’ responses ensures that the researcher has correctly communicated their perspectives (Krefting, 1991:219). Transcribed interviews were shared with interviewees in order to confirm that interpretations were accurate.

3.6.4 Audit trail

All conclusions reached and activities engaged in during the research process were meticulously documented. This was in the form of field notes, memos and computer files. Additional ways of ensuring validity of research results have been identified in research (Lewis, 2009:12; Krefting, 1991:291). These include feedback or peer examination, which is based on the same principle as member checks but involves discussing this research with an impartial colleague. This colleague, who was familiar with the research and the phenomena being studied, reviewed instruments, data and interpretations used in this research. This process was on-going. I used this peer as a sounding board for advice on ideas and decisions. These discussions added a deeper level of reflection and analysis.

3.7 Ethics

The first major consideration was to receive approval from the Western Cape Education Department to conduct research in the schools sampled. The Research

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Directorate of the Western Cape Education Department was contacted in order to determine the processes involved in granting permission for research to be conducted (Annexure 1). The forms necessary and requirements were completed and sent to the Research Directorate. On 2 March 2012 approval was granted to me to conduct research in the sampled schools (Annexure 2).

When distributing questionnaires, an accompanying letter was mailed to principals informing them of the study and requesting that Accounting teachers at the school concerned complete the questionnaire (Annexure 3). There was an accompanying letter for Accounting teachers informing them of the purpose of the study. It assured them of confidentiality and anonymity (Annexure 4).

Being granted permission by the Western Cape Education Department to conduct the study did not automatically mean that teachers and subject advisers would support the study. Each individual had to be willing to participate. All participants were made aware that their participation was voluntary. Before starting each interview, respondents were informed about the research for which the interview data was going to be used (Henning, 2004:73). This enabled respondents to give informed consent. Before the interview took place, approval was obtained from each teacher and subject adviser. Both parties signed a consent form (Annexure 5) that ensured that the participant knew the nature and purpose of the interviews and the study, and that they granted permission for the interview to be audio recorded. Participants knew that the recorded information would not be used beyond the purposes of the study.