Análisis de la interacción de CcCdnL con la subunidad β de la RNAP,

4.4.1 Definition

Case study is a strategy for doing research which involves an empirical investigation of a particular contemporary phenomenon within its real life context using multiple sources

of evidence (Robson, 1993, p. 5)

The most common use of the term ‘case’ associates the case study with a location, such as a community or organization. The emphasis tends to be upon an intensive

examination of the setting (Bryman, 2008, p. 53).

The case study ... is defined as an intensive study of a single case (or a small set of cases) with an aim to generalize across a larger set of cases of the same general type (Gerring,

2007, p. 65).

A case study is a social science method of research (Yin, 2003). It is an intensive investigation

of a specific environment or situation within its real-life context and often uses both quantitative and qualitative sources of evidence (Bryman, 2008, Robson, 1993). A case study is contained by a specific timeframe and by defined location boundaries (Gerring, 2007). It allows the researcher to focus on the detail of one or a small number of cases in order to provide richness and completeness. The intense scrutiny of the case study research can create insights which would

not be apparent to a researcher working with a larger population and in a fixed situation with preset variables and specific outcome measures (Gerring, 2007).

A case study can be exploratory, or it may strengthen or weaken a theory or idea. A case study is unique in its ability to explain how and why things come about over time (Bryman, 2008).

It is the preferred strategy to answer how and why questions when the investigator is investigating complex ‘real world’ events. This usually means that the researcher is observing, rather than controlling, the events under investigation (Yin, 2003). A case study is good at analyzing the clear cut or proximal cause and effect relationships that happen between specific events (Gerring, 2007). Pilot studies are often case studies. Here ideas and hypotheses are

developed with a view to further reproduction and investigation on a larger scale if warranted by the pilot study.

A longitudinal comparison case study is probably the most frequently used case study design

(Gerring, 2007). This type of case study observes and reports on the effects of a specific intervention which creates change over time. In a longitudinal comparison case study, if more than one case is analyzed, all cases are classified as multiple instances of the same intervention, rather than each instance being treated as a different case. The data is collated and summed as

one unit, rather than being broken down to distinguish and contrast between the cases. This is the format used for the findings in this thesis study.

4.4.2 Case Study and Representativeness

The purpose of a case study is to take the information gained and apply it to the broader world (Gerring, 2007). In other words, it must be representative, at least in some respects, of other similar situations in the wider world. Unless the case study can inform about this broader

the fundamental purpose of the case study is to focus the investigation on a single case (Robson, 1993), the ultimate goal is to use the findings to understand something which is outside the case

study itself (Gerring, 2007). This tension is resolved if the researcher makes sure that the cases within the case study are a true representation (in whatever ways might be relevant to the hypothesis or research question) of the wider world (Gerring, 2007).

The primary way of ascertaining the reliability of the case study is to replicate the study. For this to happen, the study must be made clear and operational (Yin, 2003). This will verify not just the findings but the conclusions and the context of its applicability to the wider world. There is always the possibility when there is only one case that something unknown has affected the

conclusions (Yin, 2003). In contrast, if two cases are investigated in the same case study, the conclusions are unlikely to be affected by the same unknown factor. Therefore, if the findings are the same, this gives confidence to the research findings and their applicability to the wider world (external validity). The conclusions which arise from two cases will be more powerful than if they

were from a single case only (Yin, 2003).

4.4.3 Case Study and Causality

A causal relationship is one where a ‘causal factor’ increases the probability that something

else will happen (Gerring, 2007). The idea of causality is very important in a case study. A case study can investigate a causal link in a real-life situation which is too complex for experiments or surveys to understand fully (Yin, 2003). In a good case study, solid and supported inferences must be made about how environmental or situational changes generate an observed effect (Gerring, 2007) or how certain events are normally followed by other events. A case study explores this

to apply this same causality to the wider world. The usefulness of the case study is therefore determined by how representative it is of this external world.

A good use of a case study is to investigate a process of change and the implications of this change. Unlike an experiment, a case study does not need to prove that only factor X causes the

changes in Y. A case study allows for multiple antecedents for findings. A case study can investigate a specific effect, but it does not need to manipulate this causal effect (independent variable) to do so, as would happen in an experiment.

In a case study, the inferences made about causal factors must be explained through narrative

description. This narrative has to make assumptions about the world and how it works. In a laboratory situation, these a priori assumptions are minimized and dispensed with in order to create an environment free of any perceived outside influences on the outcome. In a case study this rigor is not required. Instead, the research actively engages in a process of investigating and

tracing all reasons for any changes observed.

In a longitudinal comparison study, measurements are taken before and after an event. The

pre event observational readings are taken as a baseline which is compared to the new trend in the post event observational readings (Gerring, 2007). Inferences are developed about the events, or causal factors, which are understood to account for the variation in the findings.

4.4.4 Case Study, Methodology and Meaning

A case study is distinguished by an intensive and close focus on its subject, often using more than one research method in order to gain a deep understanding (Gerring, 2007). The researcher is required to give inferences and meaning to the findings, requiring interpretation and judgement

skills (Gerring, 2007). Convergent findings give confidence in the results, while divergent findings prompt the researcher to generate explanations, which also deepens understanding.

Having to analyze and harmonize different data streams is a safety mechanism for a case study. It means that the investigator is less likely to become overly involved in a single way of

viewing the case. It also means that it is less likely that the researcher consciously or unconsciously constructs an unwarranted positive result. The data obtained by using a single methodology may be non-typical and may not truly represent the whole population. However, this is less likely if qualitative and quantitative methodologies are used to generate two or more independent data streams which will complement and balance each other to create convergence

and insight into the overall analyses (Gerring, 2007).