As case study research is often subjected to criticism it is important that validity and reliability of a case study research is established by following the tests of construct validity, internal validity, external validity and reliability; as identified by Yin (2003b).
3.9.1 Validity
According to Bryman (2008), validity is concerned with the integrity of the conclusions that are generated from the research. Robson identifies validity as “whether the findings
are ‘really’ about what they appear to be about” (Robson, 2011: 77). Collis and Hussey
(2009: 64) identify validity as the “extent to which the research findings accurately reflect
the phenomena under study”. Whilst expressed in different terms, the underlying basis of
these definitions points out the need for establishing whether the beginning (e.g. research questions), middle (e.g. data collection and analysis), and end points (e.g.
125 conclusion) of a research study are coherent. Table 12 lists how this research sought to achieve validity and reliability.
Yin (2003b) discusses three variants of validity; construct validity, internal validity and external validity. Accordingly, construct validity relates to establishing the correct operational measures for a particular study. According to Yin (2003b) the use of multiple sources of evidence; literature review, questionnaire survey, case study, and document review in this research, is one way of ensuring construct validity. Further, interview transcripts were reviewed by the interviewees ensuring that their views were correctly recorded, as proposed by Yin (2003b). Moreover, as per Yin’s (2003b) definition of construct validity, it can be argued that establishing an appropriate research methodology from start to finish of a research study is also a way of instituting the construct validity of a research, which has been achieved via this chapter.
Table 12 - Case study tactics for establishing validity and reliability (adapted from Yin, 2003b)
Test Case study tactic used in the research
Construct validity Use of multiple sources of evidence
Review of draft case study reports by key informants
Establishing chain of evidence (i.e. audit trail; for e.g. case study protocol, interview transcripts, coding structures)
Establishing an appropriate research methodology
External validity Review of key literature Use of replication logic
Reliability Use of case study protocol
Documenting each operational stage of the research Expert opinion method
126 Internal validity relates to establishing a causal relationship where certain conditions lead to other conditions (Yin, 2003b). According to Yin (2003b), this test applies to explanatory /casual studies only. The case study stage of this research was primarily descriptive, whereas the precursory questionnaire survey was exploratory. Therefore, the test of internal validity does not apply to this research, as per the explanation put forward by Yin (2003b).
External validity refers to whether the findings of a particular study are generalisable beyond the immediate case study (Yin, 2003b). In this research, external research is achieved by a review of key literature and relating the findings to literature as well as comparing the findings at different stages of data collection; i.e. cross-case analysis and cross analysis of questionnaire survey and case study data.
As noted by Robson (2011), triangulation is a way of countering all of the threats to validity in flexible research designs such as involving case study and mixed method research. Triangulation involves the use of multiple sources of evidence throughout the study, in addition to the data collection stage as prescribed by Yin (2003b). Haigh (2004) summarised triangulation as the combination of qualitative and quantitative techniques to effectively exploit the strengths of each technique and counteract weaknesses. Denzin (2006) differentiated between four types of triangulation; data triangulation, methodological triangulation, theory triangulation, and observer triangulation.
Accordingly, opting for different data collection and analysis techniques (data triangulation), adopting a mixed method research choice (methodological triangulation), and a multi-disciplinary literature review extending well beyond the construction
127 management body of knowledge (theory triangulation) can be cited as some of the triangulation techniques adopted for this study. Observer triangulation, however, is difficult to achieve in a doctoral study where a single observer/researcher is primarily involved. Love et al (2002) articulated triangulation as an appropriate approach for extending the scope of construction management research, which is expected to be achieved in this study by adopting the aforementioned triangulation techniques.
3.9.2 Reliability
According to Yin (2003b), reliability involves determining that the operations of a study can be repeated to obtain the same results. Yin (2003b) recommends use of a case study protocol and case study database to establish reliability. These approaches were adopted within the study to enhance reliability of the study.
Whilst Yin’s (2003b) definition of reliability is very much applicable to research undertaken from a positivist point of view, it may not be readily applicable to research undertaken from an interpritivist or pragmatic point of view. This is due to the fact that researcher’s perceptions and world views have an impact on the research process. Hence, it may be difficult to reproduce the same results (Remenyi et al., 2003) in such research. Therefore, Remenyi (2003) and Easterby-Smith et al (2008) advocate demonstrating the transparency of the study through good practice guidelines. Robson (2011) recommends keeping a record of activity throughout the study. In this research, these are achieved by documenting each operational stage involved in the study within a methodology chapter and within the data analysis chapters to follow.
128
3.10
Summary and link
Establishing an appropriate research methodology is vital in addressing a research problem and achieving the research objectives, as well as establishing trustworthiness in a research. Within this chapter, philosophical positioning, research approach, strategy, choice and techniques are established whilst elucidating the reasoning behind the research methodological selections arrived at. Having reviewed key literature related to the study in Chapter 2, and establishing the research methodology in this chapter, the next stage involves reviewing and analysing primary data. Accordingly, the findings of the exploratory questionnaire survey are discussed and analysed in the next chapter.
129
4
CHAPTER 4 – FINDINGS AND ANALYSIS OF EXPLORATORY
QUESTIONNAIRE SURVEY
4.1
Introduction
The literature on key issues pertinent to this study was discussed and reviewed in Chapter 2. This was followed by establishing the research methodological framework of the study in Chapter 3. Having established why and how the research is conducted, this chapter seeks to present, discuss and analyse the outcomes of the study, observed through the mixed method research adopted. First, the findings of the exploratory questionnaire survey are discussed. As discussed under Sections 3.7.1.1 and 3.7.2.1, an exploratory questionnaire survey was conducted involving construction SMEs, and SMEs from other industry sectors, in order to inform the case study research to follow. The findings of the survey are discussed and analysed in the succeeding sub sections. In addition to construction SMEs, a sample of other SMEs was also included in the study. Comparison is made to other SMEs where relevant in order to assess how construction SMEs differ or not from SMEs in general.