Filip Roodhooft

An evaluation of vendor selection models from a total cost of ownership perspective

Abstract Many different vendor selection models have been published in the purchasing literature. However there has been no systematic approach to compare the relative efficiency of the systems. In this paper we propose to use the concept of Total Cost of Ownership as a basis for comparing vendor selection models. We illustrate the comparison with a real life data set of the purchasing problem of ball bearings at Cockerill Sambre, a Belgian multinational company in the steel industry. From a Total Cost of Ownership perspective mathematical programming models outperform rating models and multiple item models generate better results than single item models for this specific case study.

Improving the efficiency of the purchasing process using total cost of ownership information: The case of heating electrodes at Cockerill Sambre S.A.

Improving the efficiency of the purchasing process provides important opportunities to increase a firms profitability. In this paper we introduce a mathematical programming model that uses total cost of ownership information to simultaneously select suppliers and determine order quantities over a multi-period time horizon. The total cost of ownership quantifies all costs associated with the purchasing process and is based on the activities and cost drivers determined by an activity based costing system. Our approach is motivated by the purchasing problem of heating electrodes at Cockerill Sambre, a Belgian multinational steel producer. In this case quality issues account for more than 70% of the total cost of ownership making the quality of a supplier a critical success factor in the supplier selection process.

A Mathematical Programming Approach for Procurement Using Activity Based Costing

Activity Based Costing and Management are important topics in todays management accounting literature. While there has been much attention paid in the Activity Based Costing literature to customer profitability analysis, process improvement and product design, there has been far less notice taken of purchasing. In this paper we develop an Activity Based Costing approach for the determination of procurement strategies. Vendor selection using an Activity Based Costing approach is choosing the combination of suppliers for a given product group that minimizes the total costs associated with the purchasing strategy. To this end we develop a mathematical programming model where decisions involve the selection of vendors and the determination of order quantities. The system computes the total cost of ownership, thereby increasing the objectivity in the selection process and giving the opportunity for various kinds of sensitivity analysis. Copyright Blackwell Publishers Ltd 2000.

On the role of sunk costs and asset specificity in outsourcing decisions: a research note

Abstract The accounting literature has argued that firms overengage in outsourcing because they tend to ignore the transaction costs involved in buying services from external suppliers. A field experiment with managers of health care organizations shows that decision makers are actually quite sensitive to the asset specificity associated with the “buy” option in an outsourcing decision. However, they also appear inappropriately sensitive to the sunk costs inherent in most real-life outsourcing decisions, and may actually underengage in outsourcing. Prior commitment to internal procurement systematically reduced the willingness to outsource, relative to a pure “make or buy” scenario.

Time-driven activity-based costing in an outpatient clinic environment: development, relevance and managerial impact

Healthcare managers are continuously urged to provide better patient services at a lower cost. To cope with these cost pressures, healthcare management needs to improve its understanding of the relevant cost drivers. Through a case study, we show how to perform a time-driven activity-based costing of five outpatient clinics departments and provide evidence of the benefits of such an analysis.

The use of Total Cost of Ownership for strategic procurement: a company-wide management information system

We present a general company-wide management information system for defining procurement strategies. We believe that existing practices for determining purchasing strategies can be improved and a new approach developed. The system uses total cost of ownership information. We argue that mathematical programming models should be used for exploiting this information, when evaluating the firms strategic procurement options. As an example, we show how we have successfully applied our approach to develop a decision support system at Usinor, a European multinational steel company.

Public procurement of consulting services: Evidence and comparison with private companies

Purpose – The aim of this paper is to shed light on the procurement process of consulting services within the public sector and to benchmark the obtained results with practices in the private sector.Design/methodology/approach – A two‐stage research design has been used. First, in‐depth personal interviews were conducted with six users of consulting services. The second stage involved a cross‐sectional survey of purchasers of a broad range of business advisory services. This included private as well as public purchasers.Findings – It was found that the procurement process of consulting services in the public sector differs significantly from that of private companies. Further analyses indicate that purchasers from public and private organizations are equally satisfied with the results of consulting services.Research limitations/implications – The results of the study indicate that public sector organizations may need to develop new buying skills in market management, specification, competitive process, ne...

Total cost of ownership purchasing of a service: The case of airline selection at Alcatel Bell

Abstract The multiple objective problem of purchasing for business falls into two broad categories: the purchasing of components for manufacturing and the purchasing of services. Several supplier selection models have been suggested in the literature for the purchasing of production-related components. To our knowledge, no supplier selection model for the purchasing of services has been published. In this paper we elaborate on a mathematical programming model that selects suppliers of a multiple item service and simultaneously determines market shares of the suppliers selected. The methodology is based on the collection of total cost of ownership (TCO) information, quantifying all the costs associated with the purchasing process throughout the entire value chain of the firm. We apply this methodology to the real life case study of selecting airlines for 56 destinations at Alcatel Bell and have obtained TCO savings of 19.5%.

Constructing a Total Cost of Ownership supplier selection methodology based on Activity-Based Costing and mathematical programming

Abstract In this paper we elaborate on a Total Cost of Ownership (TCO) supplier selection methodology that we have constructed using real life case studies of three different industrial components groups in a firm. These case studies are presented in this article. Analysing the value chain of the firm, data on the costs generated by the purchasing policy and on supplier performance are collected using Activity-Based Costing (ABC). Since a spreadsheet cannot encompass all these costs, let alone optimise the supplier selection and inventory management policy, a mathematical programming model is used. For a specific component group the combination of suppliers is selected that minimises the TCO. TCO takes into account all costs that the purchase and the subsequent use of a component entail in the entire value chain of the company. The TCO approach goes beyond minimising purchase price and studies all costs that occur during the entire life cycle of the item in the organisation. Possible savings of between 6% and 14% of the total cost of ownership of the current purchasing policy are obtained for the three cases. ABC is not an optimisation tool as such, but provides important accurate input to the optimising mathematical program, whereas the Operations Research literature usually only distinguishes between variable and fixed costs. We show that the integration of both delivers better results in the setting we have studied.

Opening the ‘Black Box’ of Efficiency Measurement – Input Allocation in Multi-Output Settings

We develop a new data envelopment analysis (DEA)-based methodology for measuring the efficiency of decision-making units (DMUs) characterized by multiple inputs and multiple outputs. The distinguishing feature of our method is that it explicitly includes information about output-specific inputs and joint inputs in the efficiency evaluation. This method contributes to opening the “black box” of efficiency measurement in two different ways. First, including information on the input allocation substantially increases the discriminatory power of the efficiency measurement. Second, it allows us to decompose the efficiency value of a DMU into output-specific efficiency values, which facilitates the identification of the outputs the manager should focus on to remedy the observed inefficiency. We demonstrate the usefulness and managerial implications of our methodology by means of a unique data set collected from the activity-based costing (ABC) system of a large service company with 290 DMUs.