THE ECONOMICS OF CAPACITY AND MARKETING MEASURES IN A SIMPLE MANUFACTURING ENVIRONMENT

As manufacturing firms push to achieve shorter lead times and higher levels of customer service, the basic capability of underlying manufacturing processes must be reexamined. The capacity and operational variability of a process dictate a certain set of realistic performance goals. In this paper, we examine this fundamental relationship from an economic perspective using two levels of analysis. At the aggregate level, we model the manufacturing process as a single server queue and compare the traditional roles of marketing and manufacturing in setting performance and process design parameters. Insights gained at this level are incorporated into the analysis of a realistic multiserver, multistation manufacturing line. We develop an interaction decision tool to guide the selection of process and performance parameters in this more complex environment.     

THE MALL IS MY FACTORY: REFLECTIONS OF A SERVICE JUNKIE

This paper presents a personal perspective on the history, current research, and emerging topics in the field of Service Operations Management. I see research in the field evolving from a focus on classifications and operations research models in the 1970s and 1980s, to a current focus on laboratory studies, and survey- and case-based research. Selected current research is presented under the following headings: Service encounter design, service quality, drivers of service competitiveness, yield management, and the information revolution and the globalization of services. Examples of creativity in service delivery and some whimsical characteristics of service junkies are also presented.     

POWER APPROXIMATIONS FOR A TWO-ECHELON INVENTORY SYSTEM USING SERVICE LEVELS

We consider a two-echelon inventory system with one warehouse and several stores. The warehouse as well as the stores are controlled by periodic review (s, S) inventory policies. We study the interrelationship between the safety stocks at the warehouse and the stores. Stockouts at the warehouse will result in supply delays to the stores and cause the lead time to be stochastic. The stores may react by increasing their safety stock. However, there is a trade-off between the safety stock at the warehouse and the safety stock at the stores. We use a service level at the warehouse to quantify the effect of warehouse stockouts on the lead time to the stores. The service level at the warehouse is considered a decision variable to find the best compromise between the various safety stocks by minimizing the overall costs. Using power approximations for the (s, S) policies, we provide an iterative procedure for adjusting the lead time distribution to the stores; this can result in substantial savings, but it doesn't guarantee the overall optimality. Numerical studies are provided to test the accuracy of approximations. The effects of the different system parameters on the inventory policy give general guidelines for use of the policies.     

Institutional legacies in TNCs and their management through training academies: the case of transnational law firms in Italy

In this article we highlight the effects of heterogeneous institutional contexts on transnational professional service firms, a relatively poorly studied issue. Specifically, we provide empirical analysis of how the specificities of the Italian institutional context affect the activities of English legal professional service firms in Milan. This reveals the intimate connection between a variety of capitalism, place specific workplace cultures and practices, and the institution‐related challenges transnational professional service firms and all transnational corporations (TNCs) face. We also reveal the way institutionally generated differences at the level of work practices are managed in transnational law firms through worldwide training programmes designed to ‘govern’ the practices of workers in different parts of the TNC's network. This emphasizes the importance of studying attempts to manage institutional heterogeneity at the level of workplace practices, something often missed in existing mesoscale studies of TNC governance structures. Consequently, we highlight detailed empirical archaeologies that explore the direct links between institutions and practices as an important component of future research on the effects of institutions on TNCs.     

Shifting global supply networks and fast fashion: made in Turkey for Marks & Spencer

In the late 1980s and early 1990s, it was noted that retailers in Britain had started providing increased variety and fashionability to their customers, had added mid‐season purchasing to their previous two‐season calendars, and that a high fashion and low price ‘throwaway market’ had appeared on the retail scene. Since then mid‐season purchasing has evolved into purchasing throughout the year; and the ‘throwaway market’ (now called fast fashion) has become almost the norm. Here we revisit one of those British retailers (Marks & Spencer) together with its Turkish suppliers and observe a trend towards the diffusion of design capabilities to suppliers that is more widespread than is suggested in the literature. We also consider the question of how most appropriately to conceptualize the nature of these retailer‐ supplier relations in today's circumstances. We especially look into the manner in which these relations are reflected in price negotiations, the eventual distribution of the value‐added, and the nature of everyday interactions such as accreditation and reclamation practices. We conclude that even though Turkish suppliers seem to be successfully upgrading into design–a high value‐added activity–the question of whether or not this development has entailed a renegotiation of power between retailer and supplier remains a complicated one.     

Lean Production: Denial, Confirmation or Extension of Sociotechnical Systems Design?

This paper makes a comparison between the basicelements of lean production and sociotechnical systemsdesign (STSD) and compares them both with thecharacteristics of the traditional Fordist system of mass production. It argues that lean productioncan hardly be considered as an alternative to massproduction, as its proponents suggest, but is on thecontrary extending the life of mass production methods. However, lean production does appear to containsome building blocks for the innovative productionsystems that are expected to prevail in the 21stcentury. STSD, which has always presented itself as an alternative and possible successor to Fordistmethods, will need to link its traditional concerns forquality of work and flexibility of work organizationswith the new issues of continuous improvement, learning,and innovation.     

Bayesian sample size determination for phase IIA clinical trials using historical data and semi‐parametric prior's elicitation

The Simon's two‐stage design is the most commonly applied among multi‐stage designs in phase IIA clinical trials. It combines the sample sizes at the two stages in order to minimize either the expected or the maximum sample size. When the uncertainty about pre‐trial beliefs on the expected or desired response rate is high, a Bayesian alternative should be considered since it allows to deal with the entire distribution of the parameter of interest in a more natural way. In this setting, a crucial issue is how to construct a distribution from the available summaries to use as a clinical prior in a Bayesian design. In this work, we explore the Bayesian counterparts of the Simon's two‐stage design based on the predictive version of the single threshold design. This design requires specifying two prior distributions: the analysis prior, which is used to compute the posterior probabilities, and the design prior, which is employed to obtain the prior predictive distribution. While the usual approach is to build beta priors for carrying out a conjugate analysis, we derived both the analysis and the design distributions through linear combinations of B‐splines. The motivating example is the planning of the phase IIA two‐stage trial on anti‐HER2 DNA vaccine in breast cancer, where initial beliefs formed from elicited experts' opinions and historical data showed a high level of uncertainty. In a sample size determination problem, the impact of different priors is evaluated.     

PIECING TOGETHER SERVICE QUALITY: A FRAMEWORK FOR ROBUST SERVICE*

This paper addresses the issue of service design, specifically that of designing the service encounter for improved quality. We introduce a framework based on the three T's of task, treatment, and tangibles as a means of organizing the application of the diverse and growing body of service quality literature to encounter design. The framework is consistent with how successful service managers disaggregate the design problem. More importantly, we show that mutually supportive interrelationships between the three T's produce an opportunity for designing in a robustness to service failure. The framework is supported by case based evidence.     

INSIGHTS ON SERVICE SYSTEM DESIGN FROM A NORMAL APPROXIMATION TO ERLANG'S DELAY FORMULA

We show how a simple normal approximation to Erlang's delay formula can be used to analyze capacity and staffing problems in service systems that can be modeled as M/M/s queues. The numbers of servers, s, needed in an M/M/s queueing system to assure a probability of delay of, at most, p can be well approximated by s ≅ p + z_***I-p+, where z_1-p, is the (1 - p)th percentile of the standard normal distribution and ρ, the presented load on the system, is the ratio of Λ, the customer arrival rate, to μ, the service rate. We examine the accuracy of this approximation over a set of parameters typical of service operations ranging from police patrol, through telemarketing to automatic teller machines, and we demonstrate that it tends to slightly underestimate the number of servers actually needed to hit the delay probability target—adding one server to the number suggested by the above formula typically gives the exact result. More importantly, the structure of the approximation promotes operational insight by explicitly linking the number of servers with server utilization and the customer service level. Using a scenario based on an actual teleservicing operation, we show how operations managers and designers can quickly obtain insights about the trade-offs between system size, system utilization and customer service. We argue that this little used approach deserves a prominent role in the operations analyst's and operations manager's toolbags.