Data Collection

In most cases, the final theoretical framework for a research project will rest on two types of data,

namely secondary data and primary data. Secondary data is defined as existing data, which has

been collected in the past for various purposes. Primary data is defined as new data collected as

part of the research project (Page & Meyer, 2003).

In this case study, the use of primary data is preferred to existing data. The problem with existing

data is that it has not been generated specifically to address the research, and may therefore

contain potential biases or be unrepresentative of the population in which the researcher is

interested in (Page & Meyer, 2003). This research, however, focuses on some specific problems

of a certain business within a specific business environment. Thus, it is necessary to utilise

primary data collected as part of the case study.

The research focus of any study defines the population of interest. In other words, at some stage

the researcher must clearly define the circumstances under which the current research may be

generalised outside the study situation. In most cases, a population is too large for individual

exploration and only a small portion of the population, or sample, can be studied (Page & Meyer,

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Judgemental sampling is a method for obtaining non-probability samples. It consists of

respondents who, in the judgement of the researcher, will best supply the necessary information.

Such samples can be useful for the pre-testing of studies, but there is no secure basis for assuming

that they are representative of the research population. By definition, a judgemental sample never

allows for randomisation, but may exhibit some stratification (Page & Meyer, 2000). In this case

study, the selected samples meet three criteria. First of all, the selected SKU’s must be A Class

SKU’s. This is because the A Class SKU’s represent more than 80% of either total inventory

value or annual sales revenue of the company. Second, the supply of the selected SKU’s is nearly

certain because one of the focus areas of this research is the impact of demand uncertainty on

inventory. Finally, the selected SKU’s must have sufficient demand history to generate a

systematic demand forecast based on historical data.

In this case study, the following data collection methods are utilised to obtain the data: interviews,

observation, and re-collecting existing data. Interviews are common in exploratory and

descriptive studies as they provide the ability to identify the issues of relevance in circumstances

where little is known about the topic under investigation. Interviews are more flexible than a set

of structured questions in a questionnaire.

The three main types of interview techniques discussed in the literature are structured interviews,

semi structured interviews, and unstructured interviews. In a structured interview, the same

questions, with the same wording, and in the same sequence are asked of all participants involved

in the research. In semi-structured interviews, which are frequently used in qualitative analysis,

the researcher has a list of key themes, issues, and questions to be covered although the order of

the questions can be changed depending on the direction of the interview. In a completely

unstructured interview however, each interview tends to follow a completely different pattern with

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purpose of this research, the semi-structured interview technique will be utilised as this best fits

the requirements of the research.

Observational techniques are also common in exploratory and descriptive research, where the

observation condition can be either naturalistic or contrived, and where the researcher has the

option simply to observe, or to participate and observe at the same time. According to Ghauri and

Gronhaug (2005), observation as data collection technique entails both listening to and watching

other people’s behaviour in way that allows some type of learning and analytical interpretation.

The main advantage of this technique is that researchers can collect first-hand information in a

natural setting. In participant or field observation, the observer is considered a natural part of the

situation or event. The researcher is often part of a company or organisation and decides to study

a particular phenomenon within that organisation. It is also an important aspect of observation

that the process should be planned systematically in direct relation to the research question or the

relevant unit of analysis. In the context of this research, participant observation was deemed to be

an appropriate data collection technique in relation to providing information in relation to the unit

of analysis that focuses on the interaction between the different functions within the supply chain

and decision makers in achieving optimal inventory levels.

When we collect data that already exists we are usually gathering archival data, or data found in

the published literature. Both archival data and published literature must be scrutinised for their

relevance and their validity as secondary data for the study in question (Page & Meyer, 2000).