Candidate cases Methodological reflection on Case Study 3

6.3.5 Case selection

Fourteen Dutch retailers were selected from the set of candidate cases. Retailers with different competitive strategies were selected: discounters lower end of the market, retailers that focus on cost middle segment of the market, and retailers that focus on response or differentiation higher end of the market. This attempt to select a “representative” sample of cases also shows that the study was designed as a parallel case study. This representativeness was not needed for this study.

6.3.6 Hypotheses

Because the proposition in this study specified a deterministic relation, and implicitly a continuously increasing relation, the hypothesis stated that the rank order of measurement points according to the observed values of the dependent variable was exactly the same as the rank order of meas- urement points according to the observed values of the independent vari- able. Because the independent variable time access window pressure had two independent dimensions, number of time window restricted areas and time window length, two hypotheses needed to be formulated.

6.3.7 Measurement

In order to generate realistic roundtrip data for all retailers under the conditions defined by the 18 scenarios, actual current roundtrip data needed to be collected. It is described how multiple data sources were used, namely interview data face-to-face, e-mail, telephone, question- naire data, and documents. The quality of the collected data cannot be evaluated because no further detail is provided. The four dimensions of distribution costs for all 14 cases in all conditions defined by the 18 scenarios were generated by a mathematical model. A reference is pro- vided to another article in which the model is described and discussed in more detail.

6.3.8 Data presentation

Figure 6.2 presents the data generated for the different scenarios in one case, as an example. The mode of presentation is such that it directly provides the rank orders needed for testing the hypothesis.

6.3.9 Data analysis

A number of 36 rank orders were generated for each retailer four tables containing three rows and six columns. Each of these 36 rank orders is inspected to see whether their order is perfect. This implies 12 tests of hypothesis 1 three rows for four dimensions of distribution costs and 24 tests of hypothesis 2 six columns for each dimension for each retailer. Both hypotheses were confirmed.

6.3.10 Implications for the theory

Case Study 3 concludes that the two hypotheses were confirmed in all cases. The implications for the theory were not discussed, apparently considering it obvious that the proposition had been proven to be true, at least for large retailers in the Netherlands. An obvious practical implication of this study’s result is that it can be taken as a fact that an increase in the number of time access windows and a decrease in window length both result in higher distribution costs, and that, for instance, organizations of retailers could use this information in discussions with local governments and with the national government regarding the economic costs of social sustainability measures.

6.3.11 Replication strategy

Case Study 3 gives no suggestions for further replications. For the devel- opment of theory, it would be important to know to which types of retailers the proposition is applicable and to which types it is not. For instance, would the proposition be true for retailers with a system of multiple, decentralized distribution centres? Or would it be true for retailers in other countries? Hence, a replication in other countries with other types of distribution system would help to develop the theory further.

6.4 References

Allen, J., Browne, M., Tanner, G., Anderson, S., Chrisodoulou, G., and Jones, P. 2004, Analysing the potential impacts of sustainable dis- tribution measures in UK urban areas, pp. 251–262, in: Taniguchi, E. and Thompson, R.G. eds, Logistics systems for sus- tainable cities. Amsterdam: Elsevier.