A Multi‐Supplier Sourcing Problem with a Preference Ordering of Suppliers

We study a sourcing problem faced by a firm that seeks to procure a product or a component from a pool of alternative suppliers. The firm has a preference ordering of the suppliers based on factors such as their past performance, quality, service, geographical location, and financial strength, which are commonly included in a supplier scorecard system. Thus, the firm first uses available inventory from supplier 1, if any, then supplier 2, if any, and so on. The suppliers differ in costs and prices. The buyer firm seeks to determine which suppliers to purchase from and in what quantities to maximize its total expected profit subject to the preference ordering constraint. We present the optimal solution to this problem, and show that it has a portfolio structure. It consists of a sub‐set of suppliers that are ordered by their underage and overage costs. This portfolio achieves a substantial profit gain compared to sourcing from a unique supplier. We present an efficient algorithm to compute the optimal solution. Our model applies to component sourcing problems in manufacturing, merchandizing problems in retailing, and capacity reservation problems in services.     

The Lindsay transform of natural exponential families

Let μ be an infinitely divisible positive measure on R. If the measure ρ_μ is such that x^-2[ρ_μ(dx)—ρ_μ({0})δ₀(dx)] is the Lévy measure associated with μ and is infinitely divisible, we consider for all positive reals α and β the measure T_α,β(μ) which is the convolution of μ*^α and ρ_μ*β. For example, if μ is the inverse Gaussian law, then ρ_μ is a gamma law with paramter 3/2. Then T_α,β(μ) is an extension of the Lindsay transform of the first order, restricted to the distributions which are infinitely divisible. The main aim of this paper is to point out that it is possible to apply this transformation to all natural exponential families (NEF) with strictly cubic variance functions P. We then obtain NEF with variance functions of the form □ΔP(□Δ), where A is an affine function of the mean of the NEF. Some of these latter types appear scattered in the literature.     

Multivariate distributions with generalized inverse gaussian marginals,and associated poisson mixtures

Several types of multivariate extensions of the inverse Gaussian (IG) distribution and the reciprocal inverse Gaussian (RIG) distribution are proposed. Some of these types are obtained as random-additive-effect models by means of well-known convolution properties of the IG and RIG distributions, and they have one-dimensional IG or RIG marginals. They are used to define a flexible class of multivariate Poisson mixtures.     

Effect of Quality Management Systems and Total Quality Management on Productivity Before and After: Empirical Evidence from the Indian Auto Component Industry

We study the linkages between firm‐level quality initiatives such as quality management systems (QMS) and total quality management (TQM) and output productivity in the Indian auto component industry. We use externally validated quality certification and quality awards as proxies for QMS and TQM, respectively, as it is difficult to directly measure the QMS and TQM efforts of firms. We use an unbalanced panel of 220 firms and a balanced panel of 73 firms from the Indian auto component industry over the period 1993–2006 to study these links. Both parametric as well as non‐parametric approaches are used, as appropriate, to measure the rate of change in productivity and the impact of quality initiatives on productivity change during this period. We determine the proportion of productivity resulting from technical change and relative efficiency change, thus providing insights into the structure of productivity improvements. We find that TQM efforts resulted in a high rate of productivity change (11%) in the award‐winning firms after the award. On the other hand, pre‐certification productivity change due to QMS was 5% and post‐certification change was 3.6%. In the periods prior to certification, productivity change was driven mainly by technical change; whereas the source of productivity change after certification is mixed. However, prior to awards, productivity change was driven mainly by relative efficiency change, whereas post‐award productivity change was due to technical change. The results suggest that management focus on attaining certification did generate conceptual learning (linked to technical change) during the period leading to certification, but these effects were not significant after certification. The results also suggest that the TQM programs generated significant productivity gains in the long run, although setting the associated systems in place did not result in significant productivity change prior to winning awards. Thus, the study provides direct but nuanced evidence linking quality certification as well as the adoption of TQM programs to the associated conceptual and operational learning processes and their impact on the change in productivity.     

On Decisions for Integration Implementation: An Examination of Complementarities Between Product‐Process Technology Integration and Supply Chain Integration

Research has shown that both product‐process technology (PPT) integration and supply chain integration efforts produce operational benefits, yet synergies between these types of integration are not well understood. This article empirically examines strategic customer integration and supplier integration as complementary activities for PPT integration, with the aim of helping manufacturing plant managers to intelligently implement mutually supportive types of integration. We set two conditions for establishing complementarity: (i) one type of strategic integration must positively influence the adoption of another and (ii) the two types of strategic integration must exhibit a synergistic fit with respect to manufacturing plant capabilities. We test these conditions using survey results representing 224 manufacturing plants. The findings show positive complementarities between PPT integration and supplier integration with respect to quality, delivery, and process flexibility. Also, positive complementarities exist between PPT integration and customer integration with respect to quality and new product flexibility. The results extend the emerging theory of strategic value chain integration and provide guidance to manufacturing managers who wish to assemble strategic integration policies.     

Sales Forecasting with Financial Indicators and Experts' Input

We present a method for forecasting sales using financial market information and test this method on annual data for US public retailers. Our method is motivated by the permanent income hypothesis in economics, which states that the amount of consumer spending and the mix of spending between discretionary and necessity items depend on the returns achieved on equity portfolios held by consumers. Taking as input forecasts from other sources, such as equity analysts or time‐series models, we construct a market‐based forecast by augmenting the input forecast with one additional variable, lagged return on an aggregate financial market index. For this, we develop and estimate a martingale model of joint evolution of sales forecasts and the market index. We show that the market‐based forecast achieves an average 15% reduction in mean absolute percentage error compared with forecasts given by equity analysts at the same time instant on out‐of‐sample data. We extensively analyze the performance improvement using alternative model specifications and statistics. We also show that equity analysts do not incorporate lagged financial market returns in their forecasts. Our model yields correlation coefficients between retail sales and market returns for all firms in the data set. Besides forecasting, these results can be applied in risk management and hedging.     

Exponential models,brownian motion,and independence

Some examples of steep, reproductive exponential models are considered. These models are shown to possess a τ-parallel foliation in the terminology of Barndorff-Nielsen and Blaesild. The independence of certain functions follows directly from the foliation. Suppose X(t) is a Wiener process with drift where X(t) = W(t) + ct, 0 < t < T. Furthermore let Y = max [X(s), 0 < s < T]. The joint density of Y and X = X(T), the end value, is studied within the framework of an exponential model, and it is shown that Y(Y – X) is independent of X. It is further shown that Y(Y – X) suitably scaled has an exponential distribution. Further examples are considered by randomizing on T.     

Inventory Sharing in the Presence of Commodity Markets

This study investigates the value of inventory sharing in the presence of spot and forward markets. We consider a multi‐period setting where two firms process a common commodity to meet stochastic demands. They can buy and sell the commodity through both the spot and forward markets. They can also share the commodity if one has leftover inventory while the other has excess demand. We first characterize the equilibrium strategies of the two firms. Our analysis reveals that in such a context, the value of inventory sharing is low when the forward price is directly used to value the sharing transactions. We then develop a structured trans‐shipment price scheme that uses a linear combination of the spot and forward prices. We show that this method can substantially increase the value of inventory sharing. Our analysis also reveals that in the presence of liquid spot and forward markets, the value of inventory sharing mainly results from the difference of the transaction costs, and it increases if the market in which firms operate becomes more competitive.     

The perils of e‐mail communications in nonprofits

Nonprofits typically operate in a multicultural and global environment. Critical to their success is effective communications by their leaders. But effective communications is a challenge as e‐mail has become the medium of choice for communications among most nonprofit executives. Communicating with their culturally diverse stakeholders using the less personal medium of e‐mails could be jeopardized unless nonprofit executives consciously focus on how recipients might decode their message. By understanding the interactions of the linguistic, cultural, and social processes inherent in the encoding and decoding of communications, they can attenuate misunderstandings. Learning from a series of personal and damaging e‐mails experienced by one of the authors in a global nonprofit organization, the authors underline the need to be culturally sensitive in e‐mail communications in a multicultural organization. This article highlights the challenge faced by leaders and managers of nonprofits to be direct yet polite when not communicating face‐to‐face with their stakeholders.     

FIRM EXPANSION THROUGH FRANCHISING: A MODEL AND SOLUTION PROCEDURES

This paper presents a practical model for firm expansion through franchising. The model allows the possibility of opening both company-owned and franchised stores. The objective is to maximize the expected returns to the franchisor from both types of stores, subject to the total capital outlay budget and the excess capacity available at each warehouse. A relaxation for this problem is studied and a heuristic solution procedure that makes use of this relaxation is developed. Experimental results over a wide range of problem structures show this solution methodology to be very effective, with gaps between feasible solution values and upper bounds generally in the 0 to 1 percent range. An efficient branch-and-bound code also is developed. This code is tested on problems with up to 100 potential store locations and 20 regions. It is found to be at least two orders of magnitude faster than a state-of-the-art commercial integer programming package.