Base stock policies with degraded service to larger orders

We study an inventory system controlled by a base stock policy assuming a compound renewal demand process. We extend the base stock policy by incorporating rules for degrading the service of larger orders. Two specific rules are considered, denoted as Postpone(q,t) and Split(q), respectively. The parameter q distinguishes between regular orders (of size less than or equal to q) and larger orders. We develop mathematical expressions for the performance measures: order fill rate of the regular orders and average on-hand inventory level. We make numerical experiments where the postpone parameter t and the base stock levels of each rule are such that all customers (of both order types) are indifferent between the two rules. When comparing the difference in the average on-hand inventory levels, we can then make an assessment of the threshold value of the cost of splitting an order (which may otherwise be hard to quantify) in the rule Split(q). Our numerical results indicate that this threshold value is increasing in the variance of the order sizes. Based on the numerical experiment our conclusion is therefore that when the variance of the order sizes is low, then Postpone(q,t) seems to be a good option, while when the variance is high, then Split(q) is more competitive.     

On the proportionality of EU spatial ex ante coexistence regulations: A comment

In their recent article in this journal, Demont et al. (2009) discuss the effects of alternative spatial ex ante coexistence regulations (SEACERs) in the context of the EU regulatory framework. We retain from Demont et al. (2009) that small pollen barriers should be considered as a possible regulatory option in all identifiable situations in which they are as effective as large isolation distances. This idea is in accordance with the proportionality principle of the 2003 EC Recommendation. But further analysis of how consumer choice and consumer welfare are affected should be conducted before supporting the idea that SEACERs should be flexible, that is that GMO farmers should always have the option of paying their non-GMO neighbours to implement the SEACERs in their own fields. We reject the authors’ argument that pollen barriers are necessarily more easily negotiable among neighbours (more “flexible”) than are isolation distances. We contest the relation of proportionality to the size of market signals for IP products. We contest the idea of shifting coexistence regulation from ex ante to ex post. We believe that any economic analysis of coexistence measures should include their welfare effects on consumers as well as on producers.     

Using actors' perceptions of network roles and positions to understand network dynamics

This article explores network dynamics by analysing how actors make sense of time and space in business networks, and how they act based on these perceptions. The time dimension is understood here as actors' perceptions of past, present and future changes in their network. The space dimension is understood, first, in terms of the network position a company holds in relation to its business partners, and secondly, in terms of the network role it enacts. As such, this study relates three pivotal concepts in industrial marketing: network change, network position, and network role. The link between these three relates to the interdependencies within a network, in that if one company attempts to change its position, this will in turn affect the position of other companies. Moreover, actors' attempts to change their position or role in the network are directed by their subjective sensemaking or perceptions of their surrounding network. In this article we posit that in order to understand network dynamics we must analyse how actors attempt to affect change based on their perceptions of their positions and roles in their network environment. Our analysis suggests that although there are similarities between perceptions by actors holding similar positions in the network, such network positions alone cannot explain their actions. Rather, differences in actors' interpretations and enactments of their network role are necessary to explain their networking activities. We use an extensive case study of the changing distribution structure for seafood in Norway and Japan to exemplify these points.     

Does data portability facilitate entry?

Data portability rules are generally thought to encourage consumers to switch between different service providers and facilitate entry of new firms. Some of these rules, however, only apply to data “provided by” the consumer (data subject), e.g., purchasing patterns. Data “derived by” a firm (data controller) with the help of data analytics, e.g., recommendations derived from purchasing patterns, does not fall under data portability rules. We show that, under the current legislation along with extensive use of data analytics, data portability may hinder switching and entry due to the demand-expansion effect: the prospect of easier switching due to data portability may entice consumers to provide even more data to the incumbent, which strengthens the incumbency advantage. Hence, the effectiveness of data portability in fostering competition will depend on what types of data are portable. More generally, in analysing the effectiveness of polices aiming at reducing ex post switching costs, it is important to take into account their impacts on ex ante actions that build up endogenous entry barrier.     

Partial monitoring,adverse selection,and the internal efficiency of the firm

The paper investigates an adverse selection model with monitoring of managerial effort. In contrast to the literature, we assume that the manager can be punished only if his effort is below a certain level that is monitored by the principal. Surprisingly, the optimal labor contract may induce an equilibrium effort which is lower than in the standard model without monitoring. This result holds for any discrete distribution of managerial types. In the continuous type case, the optimal contracts for high-quality (low-quality) managers are purely output-dependent (effort-dependent).     

Access regulation and geographic deployment of a new generation infrastructure

This paper addresses the impact of regulatory policy on levels of infrastructure deployment and derived welfare in the telecommunications sector. The model considers two potentially coexisting and partially competing technologies (the “old generation network” – OGN – and the “new” generation network – NGN). This framework allows us to show that the “regulation defining access charge in order to maximize infrastructure deployment” is strictly equivalent to the case in which “no regulation applies”. We also derive from the model that these two types of regulation induce higher social welfare, but lower numbers of NGN consumers, compared to the “ex post access prices” regulation. Finally, we show that the level of infrastructure deployment (as well as social welfare and number of NGN consumers) will be highest if both investment and access charge decisions are taken by the welfare maximizing regulator. This suggests that the social optimum will be achieved through a calls-for-tender process that includes deployment and access charge requirements.     

Disaggregation and consolidation of imperfect quality shipments in an extended EPQ model

We consider a standard economic production quantity (EPQ) model. Due to manufacturing variability, a fraction P of the produced inventory will have imperfect quality, where P is a random variable with a known distribution. We consider a 100% inspection policy and further assume that the inspection rate is larger than that of production. Thus, all imperfect quality items will be detected by the end of the production cycle. For such an augmented EPQ model, we first derive the new optimal production quantity assuming that the imperfect quality items are salvaged once at the end of every production cycle. Then, we extend this base model to allow for disaggregating the shipments of imperfect quality items during a single production run. Finally, we consider aggregating (or consolidating) the shipments of imperfect items over multiple production runs. Under both scenarios we derive closed-form expressions for both the economic production quantity and the batching policy, and show that our desegregation/consolidation schemes can lead to significant cost savings over the base model.     

Service productivity and service quality: A necessary trade-off?

This paper is about service productivity and perceived service quality. Both a high service productivity and a high customer perceived quality are two main drivers of good performances in service companies and they simultaneously occur as a consequence of a synergy of several drivers such as employees' competences and motivation, organizational efficiency, technical devices availability, information technologies employment, etc. In scientific literature a trade-off between productivity and perceived service quality is asserted and several cases derived both by market observations and academic research could bear such trade-off out. But, is it possible to state that, under some circumstances, such a trade-off between productivity and perceived service quality could be avoided? And if yes, why such certified substitution should not work?In this paper, in order to trace some theoretical answer to the above questions, a managerial model based both on service science and production economics will be proposed. The model aims to find out some key causes that allow to explain the foundations of the mentioned trade-off and the potential conditions for its overcoming; moreover, such model will be employed in order to integrate services' productivity function with new variables and to provide some managerial guidelines for improving service management.     

Towards a model of dynamic capabilities in innovation-based competitive strategy: Insights from project-oriented service firms

With the growing significance of services in most developed economies, there is an increased interest in the role of service innovation in service firm competitive strategy. Despite growing literature on service innovation, it remains fragmented reflecting the need for a model that captures key antecedents driving the service innovation-based competitive advantage process. Building on extant literature and using thirteen in-depth interviews with CEOs of project-oriented service firms, this paper presents a model of innovation-based competitive advantage. The emergent model suggests that entrepreneurial service firms pursuing innovation carefully select and use dynamic capabilities that enable them to achieve greater innovation and sustained competitive advantage. Our findings indicate that firms purposefully use create, extend and modify processes to build and nurture key dynamic capabilities. The paper presents a set of theoretical propositions to guide future research. Implications for theory and practice are discussed. Finally, directions for future research are outlined.     

Multicollinearity: How common factors cause Type 1 errors in multivariate regression

Research Summary : In multivariate regression analyses of correlated variables, we sometimes observe pairs of estimated beta coefficients large in absolute magnitude and opposite in sign. T‐statistics are also large, suggesting meaningful findings. I found 64 recently published Strategic Management Journal articles with results exhibiting these characteristics. In this article, I demonstrate that such results may be Type 1 errors (false positives): If regressors are correlated via an unobservable common factor, estimated beta coefficients will misleadingly tend toward infinite magnitudes in opposite directions, even if the variables’ real effects are small and of the same sign. Diagnostics such as Variance Inflation Factors (VIF) will misleadingly validate Type 1 errors as legitimate results. After establishing general results via mathematical analysis and simulation, I provide guidelines for detection and mitigation. Managerial Summary : This article demonstrates mathematically how regression analyses with correlated independent variables may generate beta coefficients of opposite sign to the variables’ true effects. To assess the likelihood of this possibility, I propose that: if (a) absolute correlation of two independent variables is about ±0.3 or more (smaller correlations may be problematic for large data sets), (b) the two variables have beta coefficients of opposite sign, if correlated positively, and of the same sign, if correlated negatively, and (c) the bivariate correlation of one independent variable with the dependent variable is of the opposite sign from the beta coefficient, then the beta might be a false positive. To facilitate such analysis, authors should provide complete correlation tables, including dependent variables, interaction terms, and quadratic terms.     

Exact and approximated calculation of the cycle service level in a continuous review policy

The paper proposes a method to compute the exact cycle service level for (s, Q) continuous review policy in the presence of undershoots and discrete demand in the discrete time domain. Prior to this, it is necessary to review the definition of the cycle service level in order to avoid the problems that can be found when applied it to the periodic review policy. Therefore, the aim of this paper is: (a) to review the definitions of the cycle service level when applied to continuous review policies; (b) to develop an exact calculation method of the CSL for a continuous review policy when undershoots are allowed and demand is discrete; and (c) to examine some common believes about the cycle service properties. Finally, the bias obtained when the service cycle level is estimated applying the common assumption of neglecting undershoots at the order point is illustrated with some numerical examples which show that it may lead to significant deviations to be ignored.     

Impact of frequency of alignment of physical and information system inventories on out of stocks: A simulation study

Inaccuracy in the information system inventory as compared to the physical inventory may lead to out of stocks. Inaccuracy may occur for many reasons, a principal one being random losses such as theft. One way to reduce this inaccuracy is to adjust the inventory information in the systems at some regular frequency. Such alignments are quite expensive in practice. Thus how often to align the two inventories is the focus of this research. A simulation model is employed to investigate the effect of such loss defined by the stock loss parameter (λ) and the frequent alignment of physical and information system inventories on the stockout (S_out) and average inventory (I). A term to be called the effective value of stock loss parameter is introduced to signify the effect of frequency of alignment (f) on S_out. The results derived in this study provide a powerful tool in the hands of an inventory manager. It has been noted that, so far as stockout is concerned, by selecting a moderate value of alignment frequency (f), the effective value of stock loss parameter (λ_e) can be reduced to∼ λ/f. The accuracy of S_out and I values across a number of runs in the simulation studies, sensitivity of S_out and I on various parameters and the nature of stochastic demand distribution, and application of these results with or without deployment of RFID to reduce the loss due to stockout are also discussed. The results, verified under various scenarios, indicate that there is a significant reduction in stockout loss when the alignment is done monthly vs. annually, but it does not add much value beyond a monthly check.     

A stochastic inventory model of dual sourced supply chain with lead-time reduction

Recently, the amount of literature on analyzing the effects of investment strategies to control lead times has been increasing. Issues on investment to reduce lead times are important because variability in lead time between successive stages often has a great effect on the coordination of supply chain.This paper considers dual-sourcing models with stochastic lead times and constant unit demand in which lead times are reduced at a cost that can be viewed as an investment. In order to obtain an analytically tractable model, the distributions of lead times for two suppliers are assumed to be exponential. In our two-supplier model, we will concentrate on lead times as random variables, which are made endogenous in the stochastic lead-time model through “expediting factors”, the constants of proportionality between the expedited lead times and ordinary lead times, as was done by Bookbinder and Çakanyildirim (Eur. J. Oper. Res. 115 (1999) 300).Firstly, we determine the order quantity (Q), reorder point level (r), and order splitting proportion (k₁) in the case of no lead-time reduction. Using the (Q,r) found, we decide the expediting factors and new k₁ in the case of lead-time reduction. We compare the expected total cost per unit time for the two models and investigate savings. Additionally, sensitivity analyses are conducted with respect to the various cost parameter ranges, and remarks are made for further research.     

An inventory reservation problem with nesting and fill rate-based performance measures

In many inventory settings companies wish to provide customer-differentiated service levels. These may, for example, be motivated by differences in the perceived customer lifetime value or by specific contractual agreements. One approach to provide differentiated service levels is to reserve some portion of the available inventory exclusively for specific customer classes. Existing approaches to inventory reservation are typically based on the assumption that a company can assign a customer specific revenue or penalty cost to any order or unit of demand filled or unfulfilled. In practice, however, it is usually extremely difficult to accurately estimate (especially long term) monetary implications of meeting or not meeting customer demand and corresponding service level requirements. The research presented in this paper addresses the problem of setting appropriate inventory reservations for different customer classes based on fill rate-based performance measures. We model a single period inventory reservation problem with two customer classes and nesting. We develop exact expressions for two conflicting performance measures: (1) the expected fill rate of high priority customers and (2) the expected loss in the system fill rate induced by inventory reservation. With these expressions a decision maker can analyze the tradeoff between the loss in overall system performance and the higher expected fill rates for prioritized customers. We provide analytical insights into the effects of nesting and the impact of relevant problem parameters on these two performance measures. The analytical insights are illustrated and highlighted through a set of numerical examples. Although we limit our analysis to a single period inventory reservation problem, we expect that our results can be utilized in a wide range of problem settings in which a decision maker has to ration a perishable resource among different classes of customers.     

Access Pricing and Network Expansion in Natural Gas Markets

In this paper, we discuss different indirect approaches to cope with local market power in natural gas markets, in particular the extension of pipeline capacity as an instrument to combat nodal market power. One perspective, as expressed in Cremer and Laffont (Eur. Econ. Rev. 46:928–935, 2002) is that a discriminatory access price can correct for market failure and induce an increase in output. We argue, on the contrary, that the opposite holds: non-discriminatory access to the pipeline system will lead to overcapacity, and is thus the preferable strategy.     

Support service is key for technology transfer to China

China, under the direction of its new political leadership, is extremely interested in purchasing the most up-to-date technology. However, still being a less-developed nation, there is some doubt about her ability to absorb this high-level technology. If the U.S. industrial marketers hesitate to sell this technology, China will buy it from other industrialized countries. The authors maintain that the U.S. industrial marketers must sell the high-level technology to China. However, they also must make sure that this technology will be transferred successfully. In order to assure the success, the authors suggest that special attention be paid to the development of marketing support service systems as highly technical industrial products are sold to China. These systems will at least temporarily overcome existing barriers to technology transfer and hence will facilitate smooth and enduring technology transfers in the long run.     

Freemium as optimal menu pricing

In online contents markets, content providers collect revenues from both consumers and advertisers by segmenting consumers who are willing to avoid advertisements and who are not. To analyze such situations, I construct a model of menu pricing by advertising platforms in two-sided markets. I find that, under certain condition, although a monopolistic platform can choose any menu of price-advertisement pairs, the optimal menu consists of only two services: ad-supported basic service and ad-free premium service. In addition, if the willingness to pay of advertisers is sufficiently high, the basic service is offered for free. This menu pricing is well known as freemium. Furthermore, this binary structure remains to hold under several extensions including duopoly platform competition.     

Regulatory decision errors,Legal Uncertainty and welfare: A general treatment

We provide a general treatment of the implications for welfare of various sources of legal uncertainty facing agents about the decisions made by a regulatory authority. We distinguish the legal uncertainty from the decision errors made by the authority. While an increase in decision errors will always reduce welfare, for any given level of decision errors, information structures involving more legal uncertainty can improve welfare. This holds always when sanctions are set at their optimal level. This transforms radically one's perception about the “costs” of legal uncertainty. We also provide general proofs for two results, previously established under restrictive assumptions.     

Freedom of access to the radio spectrum for satellite communications

A conference will open on 8 August 1985 under ITU auspices to consider major procedural changes in the international regulation of the use of the radio spectrum by geostationary satellites. There has been strong pressure for the introduction of a priori orbit/ spectrum planning for, for example, the fixed-satellite service from countries which foresee that they may lose their option to set up domestic satellite networks under the present ptocedure. However, reform of the present procedures, rather than radical change, would give better assurance that the real needs of all countries will be met.