Significado de las variables

Burgess et al. (2006,) using Wacker’s (1998) classification scheme, suggest that research methods can be broadly divided into two groups: analytical and empirical. Analytical research methods primarily use logical, mathematical and / or mathematical - statistical methods, while in the empirical research major classification, the methodology must use data from external organizations or businesses to test if relationships hold in the external world (Wacker, 1998). Empirical research methods could be classified more correctly as ‘real world’ empirical methodologies. Analytical methods are further categorized as conceptual, mathematical or statistical, while empirical methods include experimental design, statistical sampling or case studies (single or multiple). These have been illustrated in Table 5.2:

In this thesis, the first stage of the research is the development of a conceptual framework, which is developed using the existing conceptual literature in the field of operations management, logistics and supply chain management, and

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secondary case examples. As such, it is analytical and deductive in nature. In the second stage, empirical research is conducted in order to inform the conceptual model presented in Chapter 3, and also gain insights into agile supply chain management practices in a global context. As a result, this research integrates both the analytical and empirical research approaches.

Types of research included Importance to operations management theory building Conceptual Futures research scenarios, introspective reflection, hermeneutics, conceptual modelling

Develops new logical relationships for conceptual models of theory Mathematical Reason / logical theorem providing, normative analytical modelling, descriptive analytical modelling, prototyping, physical modelling, laboratory experiments, mathematical simulation Explores the mathematical conditions underlying the relationships used in theory-building Analytical

research

Statistical Mathematical statistical modelling

Integrates the other five methods into a single theory for empirical investigation Experimental design Empirical experimental design, descriptive analytical modelling

Tests and verifies casual relationships between variables Statistical sampling Action research structured and unstructured research, surveying, historical analysis, expert panels

Tests the theory by investigating statistical relationships to verify their existence in larger populations Empirical research Case studies (single or multiple)

Field studies, case studies

Tests and develops complex relationships between variables to suggest new theory.

Table 2 5.2. Analytical and Empirical Research

Table 5.2. Analytical and Empirical Research (Adapted from Wacker, 1998) In choosing the type of empirical research to be conducted, a multiple case study methodology was deemed most appropriate, after reviewing all three empirical research approaches at the start of the research project.

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‘Experimental design’ was quickly dismissed because it would be impossible for the author to control certain variables in an open system in which the companies under study operate. Purely questionnaire based ‘statistical sampling’, involving a large group of companies, was also rejected because it would lack sufficient depth, particularly in such a new area of study such as agile supply networks (Edwards et al., 2001). There are also other drawbacks to statistical research such as model limitation, the possible omission of crucial variables, the abstract and remote character of key variables, the casual complexity of multivariate analysis, and the difficulty in understanding, interpreting and especially implementing the results of studies (Bonoma, 1985; Meredith, 1998).

‘A case study examines a contemporary phenomenon within its natural settings and the boundaries between the phenomenon and context are not clearly evident’ (Yin, 2003, p.23). The case study represents a specific tradition within the qualitative research paradigm (Creswell, 1998) and attempts to arrive at a comprehensive understanding of the event under study but at the same time to develop more general theoretical statements about regularities in the observed phenomena (Fidel, 1984). Because case studies are intended to take the reader of the research into the world of the subject, case studies can provide a much richer and more vivid picture of the phenomena under study than other, more analytical methods (Marshall and Rossman, 1999). Yin (2003) argues that case study research is particularly suitable for exploring ‘why’, ‘what’ and ‘how’ research questions and examines contemporary events, and this is one of the main reasons why it was adopted for this thesis. Wacker (1998) considers that empirical case studies provide new conceptual insights by investigating individual cases for an in-depth understanding of the complex external world, while empirical statistical research methodologies verify models for their empirical validity in larger populations to reduce the number of relationships in future research. Meredith (1998) and Voss et al. (2002) put emphasis on the fact that case studies include the richness of their explanations, having validity with practitioners and their facilitation of theory testing, extension and refinement.

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Benbasat et al. (1987) also indicated that case research is very appropriate for those problems in which research and theory are at their early, formative stage, the variables are still unknown and the phenomenon is not very well understood. Strauss and Corbin (1990) and Yin (2003) argue that the purpose of the case study approach is not to generalise findings into predictions about a population but to ground the development of theory in empirical observations and further refine it through the test of reality.

Supply Chain Management has long been acknowledged as an area in which researchers often find themselves trailing behind practitioners. Thus, the case study research strategy is well-suited for capturing the knowledge of practitioners and developing theories from it (Meredith, 1998).

To sum up, there are four main reasons why this research adopted the case study approach:

- Agile Supply Chain Management in a global context is poorly understood from an academic perspective and few studies have been conducted in it. Case study research can provide in-depth insights into it.

- The research question formulated in Chapter 4 is exploratory and explanatory in nature, a ‘how’ question, and the case study approach is most suitable for answering it

- A qualitative study of companies operating in a dynamic, global environment will allow a closer exploration of the issues identified and the development of theoretical and practical insights into the research issues, underpinning the belief that knowledge and our understanding of it is socially constructed (Berger and Luckmann, 1966; Gergen, 1999). - Due to the characteristics of the UK mass fashion sector, with a few very

large retailers and many small independent manufacturers, mainly located overseas, a small response rate was anticipated with regard to a mail survey. This assumptions was confirmed during the case sampling period of the research, when overseas suppliers proved very reluctant to sacrifice time for the purpose of this research. The characteristics of the UK mass fashion retail sector discussed in the previous chapter also meant that there is a limited number of large retailers that could participate in the study.

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In addition, although a single in-depth case study with a major UK fashion retailer has been considered, it was quickly rejected as providing too narrow an understanding of agile supply chain management practices. A single case study would also have more potential for bias as a result of, for example, exaggerating easily available data. After careful consideration, a two case-study research design was decided upon, with various companies across the two supply chains, in order to gain both the sufficient research depth and width. At the same time, multiple cases research is considered more compelling and the overall study more robust (Yin, 1994) as they have higher external validity and help guard against observer bias (Voss et al., 2002; Yin, 2003).

Authors also caution that there are disadvantages to choosing a case study methodology and much of its criticism is related to validity and reliability (Voss et al., 2002; Yin, 2003). Related to its validity, authors such as Gill and Johnson (2002) and (Saunders et al., 2007) distinguish between external validity, internal validity and construct validity.

- External validity is important when considering the rigor of the case study and is called ‘transferability’ by some researchers (Marshall and Rossman, 1989; Creswell, 1994; Stuart et al., 2002). It reflects the extent to which any research findings can be generalised or extrapolated beyond the immediate research sample or setting in which the research took place Gill and Johnson (2002). As opposed to statistical generalisation, Yin (2003) argues that case studies rely on ‘analytical’ generalisation, which requires the researcher to generalise a particular set of results to some broader theory.

- Internal validity reflects whether or not what is determined as the cause or stimuli actually produces what has been interpreted as the effects or responses. Yin (2003) considers that internal validity is a concern to explanatory case studies only, where the researcher is trying to demonstrate weather there is a casual relationship between the independent variable and the dependent variables.

- Construct validity reflects the extent to which the measurement questions actually measure the presence of those constructs they seek to measure.

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It refers to the establishment of the proper operational measures for the concepts being studies.

- Reliability is the extent to which a case study’s operations can be repeated with the same results. Gill and Johnson (2002) consider that it should be possible for another researcher to replicate the original research using the same subjects and the same research design under the same conditions.

Based on the work of Yin (2003) and Trochim (2002), Table 5.3. summarises the tactics adopted in this research in order to assure validity and reliability.