Data analysis How to test a deterministic relation with a case study

Rank orders might differ considerably or only slightly e.g. when the rank orders differ only for two measurements out of a large number. If the rank order differs only slightly it is tempting to conclude that the hypothesis is almost confirmed. This is only acceptable if, in a large number of instances, only a few exceptions occur, and a pragmatic deterministic view is chosen. Normally the hypothesis is rejected if the predicted pattern does not match with the measured pattern.

6.1.8 Implications for the theory

The issues regarding the implications for theory are the same as for all theory-testing case studies. See 5.1.8 for a discussion of this topic.

6.1.9 Replication strategy

The issues regarding the replication strategy are the same as for all theory-testing case studies. See 5.1.9 for a discussion of this topic.

6.2 Case Study 3: Theory-testing research: testing a deterministic relation

The influences of urban time access windows on retailers’ distribution costs 1 by Hans Quak

6.2.1 Introduction

Urban freight transport is crucial to maintain the current urbanized way of living. It is vital to trade and leisure activities in cities as well as to the liveability in these areas. However, transport also causes noise, emissions, congestion, decreased city accessibility, fossil fuel use, visual intrusion, vibration, consequences of emissions on public health, injuries 1 This chapter is based on: Quak, H.J. and De Koster, M.B.M., Exploring retailers’ sensitivity to local sustain- ability policies, Journal of Operations Management 2007, doi:10.1016j. jom.2007.01.020. and deaths resulting from traffic accidents, loss of greenfield sites and open space, and damage to infrastructure and historical buildings from heavy vehicles Browne and Allen, 1999; Banister et al., 2000. Currently, these negative effects have the upper hand in residents’ and policy makers’ perceptions of urban freight transport and form the motivation for policies aimed at reducing it. One of the most popular urban freight transport policy measures aiming at improving social sustainability in urban areas, especially in Europe, is the use of time access windows OECD 2003. A time access window forces all distribution activities to be carried out within the time window period at the time window area. The objective of time windows is to improve the quality of the city centres, by reducing the perceived negative impacts caused by large vehicles in shopping centres, as well as to separate the freight carriers from the shopping pub- lic that uses cars to visit the shopping areas Allen et al., 2004; Munuzuri et al., 2005. The use of time windows has increased in the Netherlands over recent years. In 1998, 41 per cent of the 278 largest Dutch munici- palities used time windows. This increased to 53 per cent in 2002. The larger the municipality, the more likely it is that it uses time windows: of the Dutch top 100 municipalities, 71 per cent used time windows in 2002 and all municipalities in the top 20 did so. In 2002, the average time win- dow length was about 4.5 hours PSD 2002. Many carriers and large retail chains consider time windows one of their biggest problems in delivering to their shops in urban areas Crum and Vossen, 2000. Groothedde and Uil 2004 estimate that the current cost caused by time window restrictions for Dutch retail is about €270 million annually.

6.2.2 Theory

6.2.2.1 Object of study

The object of study is the distribution activities by retailers from a retailers’ distribution centre to the shops during one week.

6.2.2.2 Concepts

The concepts of interest are: ■ Time access window pressure. This pressure consists of a the number of windows number of areas in which time access win- dows are present and b the length of these time windows.