This study employed a triangulation mixed methods approach that generated both the quantitative and qualitative data. This approach was favoured since the weaknesses of
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one data set are complemented by the strengths of the other data set (Creswell, 2012). However, ensuring validity and reliability of the integrated data was complex and cumbersome. The literature has described many different concepts and terms of validity and reliability that have been used separately for quantitative and qualitative data (Cohen et al., 2007; Lincoln & Guba, 1985; Maxwell, 1992). As such, when integrating quantitative and qualitative data, Onwuegbuzie and Johnson (2006) argued that the use of bilingual nomenclature is appropriate. They recommended that the use of the term “legitimation” (p. 48) is more appropriate than the terms validity and reliability. For the purpose of this study, the concepts of validity and trustworthiness were used to enhance the quality of the quantitative and qualitative data for this study.
3.9.1 Validity
The validity of this study was maximised in order to generate what it intended to generate (Burns, 2000). While there are many different concepts of validity used for quantitative and qualitative methods, this study ensured that the construct validity and cultural validity were maximised.
Construct Validity
Based on its theoretical framework, this study integrated key research areas into a coherent conceptual framework that premised to enhance science teachers’ PCK for use in the SBA of practical work. As such, the construct validity for this study involved the process whereby the concepts and key ideas in the conceptual framework were well translated or transformed into the construct of the items in the instruments used for data collection (Cohen et al., 2007; Drost, 2011). Underpinned by both the quantitative and qualitative methods, construct validity for both – the survey instrument and the semi-structured interviews were examined and validated for the notion of fitness for purpose (Cohen et al., 2007). Subsequently, in order to substantiate the construct validity for the two instruments, a process involving face validity, content validity and convergent validity were employed for this study (Trochim & Donnelly, 2008).
Initially, face validity was used to examine how well the abstract concepts and ideas were translated into the instruments used and whether participants were able to respond
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to the items in ways that were intended (Drost, 2011). This involved seeking the opinions from likely participants (Munby, 1997). Therefore, the researcher asked five other Solomon Islands students who were familiar with the SBA of physics concepts and were studying at Curtin University to provide their responses to the survey items and interview questions. Their responses were assessed to substantiate the fitness for purpose. That is, whether they responded in ways that were expected according to the constructs. The face validity was a weak form of construct validity (Drost, 2011).
Subsequently, content validity was also used to assess whether the content of the instruments comprehensively covered the domains they purported to cover (Cohen et al., 2007). That is, to test whether the content domain of the items were theoretically sound and were actually represented in the constructs themselves. This involved seeking the judgements of five other doctoral colleagues and research experts at the STEM Education Research Group at Curtin University. In addition, convergent validity was used to examine whether the survey items in a specific scale were similar to other items of the same scale (Drost, 2011). The purpose was to construct a multiscale survey that can provide a means to determine whether items within the same scale were tapping into the same construct. As well, to check whether each scale was assessing a distinct construct from the other scales in the survey. Similarly, the open- ended questions for the semi-structured interview were constructed with distinct guided themes.
Cultural Validity
Apart from the construct validity one significant research validity that is generally ignored is cultural validity (Jadhav, 2009). As such, this study ensured that cultural validity was not ignored, but instead was a key inclusion. While the validity of an instrument ensures that it is actually measuring what it intended to measure, “cultural validity extends to contextualise validity within the specific community being studied” (Jadhav, 2009, p. 92). It involves the researcher, being sensitive to the cultural values of the participants. “This could include:…identifying and understanding salient terms as used in the target culture;…checking interpretations and translations of data with native speakers; and being aware of one’s own cultural filters as a researcher” (Morgan, 2005, p. 1). Additionally, cultural validity ensures that the researcher is the appropriate person to conduct the research and appropriate participants are selected as
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well as, information is translated through culturally appropriate means (Joy, 2003). As such, cultural validity ensures that what is measured is culturally appropriate and adds value to the authenticity and truthfulness of the study.
Being a Solomon Islander, the researcher was not alien to the sociocultural context of this study as well as to the participants. The researcher was aware and sensitive to the participants’ circumstances as well as their sociocultural and geopolitical environments (Cohen et al., 2007). That said, the researcher did not occupy a position of influence or status within the sample population, and was well accepted by participants. The sensitivity to the sociocultural context of this study was crucial for its success. It was a way of showing respect and understanding. The participants felt at ease in the comfort of their own lived environments, when they related and identified strongly to researcher. In this environment, the participants were able to freely express their views and experiences with regards to the phenomenon investigated. As a result, the researcher was able develop a better rapport and delve deeper to seek meanings and interpretations in the context. Added to that, the participants were able to relate and make sense of their lives and understand their own experiences (Bishop, 1997).
The researcher being a Solomon Islander was also a bonus. The researcher was also able to translate information in a way that was socially and culturally appropriate to the participants as well as the other gatekeepers. As such, the researcher was able to effectively communicate, co-construct meaning and interpretations as well as analyse and develop inferences from participants’ data that were collected in this study. Consequently, the cultural validity of this study ensured that data collected was contextually and socio-culturally appropriate.
3.9.2 Trustworthiness
While trustworthiness is a term used mainly in qualitative research (Guba, 1981), it has the same concept as validity and reliability in quantitative research (Golafshani, 2003). The constructs of trustworthiness in qualitative research are comparable to the quality criteria in quantitative research (Lincoln & Guba, 1985; Shenton, 2004). That is, credibility in qualitative research is comparable to internal validity in quantitative research. Similarly, transferability is comparable to external validity; dependability is comparable to reliability, and confirmability is comparable to objectivity (Shenton,
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2004). Actually, trustworthiness ensures that a researcher presents a convincing case that demonstrated “something or someone may be trusted or relied upon to be true” (Bell & Cowie, 1996, p. 11). Over the years both qualitative and quantitative researchers seek to ensure that their research was trustworthy (Guba, 1981; Shenton, 2004). In saying that, the trustworthiness of this study was ensured by addressing the provisions that are outlined next.
The researcher was familiar with the phenomenon investigated as well as the sociocultural context of the participants. So the researcher was in a better position to construct contextual and conceptual interpretations of the participants’ own and multiple constructs. As such, the researcher had confidence to maximise the credibility (internal validity) of the data generated.
The researcher used different forms of triangulation (Cohen et al., 2007; Shenton, 2004). One form of triangulation was the use of different methods such as, surveys, one-on-one interviews and focus group interview. The data from the different sources were triangulated to strengthen the results for this study. In addition, based on the assumption that participant’s views and experiences were subjective, another form of triangulation involved the random selection of participants from several high schools within different contexts as multiple cases (Guba, 1981, Merriam, 1998). Consequently, data were generated from multiple constructions of views and experiences from different contexts. The multiple constructions of views had provided a rich and credible data that can be transferable (external validity) to similar, but diverse cases and or contexts.
The researcher sought the assistance of an independent Solomon Islander in Perth, Western Australia who fluently speaks and writes both Pidgin and English to cross validate the data generated from audio recordings. That involved repeated listening to the recorded interviews in Pidgin while reading the written transcripts in English. By doing that, back translations as well as verification of meanings to the actual spoken words were simultaneously validated. Such process ensured that the data generated was the result of the views and experiences of the participants and not of the researcher (Miles & Huberman, 1994). The researcher used this provision to enhance the confirmability (objectivity) of the generated data.
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The researcher airmailed each interview participant their written transcripts for verification and validation purposes. While most interviewed participants indicated that it was not a concern for them to verify the data they provided, the researcher still ensured that trust was established with the participants.
Finally, this study is trustworthy since the researcher has provided a detailed description of the research design and implementation process as well as the result. With such a detail, other future researchers can use the information from this study as a “prototype model” (Shenton, 2004, p. 71). Consequently, future researchers can maximised the dependability (reliability) of the information provided in this present study (Lincoln & Guba, 1985; Shenton, 2004).