3 rd Workshop on Efficiency and Productivity Analysis. Book of Abstracts & List of Participants

Transcription

1 3 rd Workshop on Efficiency and Productivity Analysis Book of Abstracts & List of Participants 25 th September, 2009 Universidade Católica Portuguesa, Centro Regional do Porto Rua Diogo Botelho, 1327, Porto Organising Commitee: Maria Conceição Portela, Universidade Católica Portuguesa, Centro Regional Porto. Ana Camanho, Faculdade de Engenharia, Universidade do Porto.

2 PROGRAMME 1

3 REGISTRATION AND OPENING SESSION (9h00-9h30) Plenary Session Emmanuel Thanassoulis (Aston University, UK) 9h30-10h10 Title: Efficiency and productivity in higher education: An assessment of administration in universities in the United Kingdom Plenary Session Geraint Johnes and Jill Johnes (Lancaster University, UK) 10h10-10h50 Title: Strategic responses to companies own past performance: Why do some firms fare better than others? COFFEE BREAK (10h50-11h15) Session 1: DEA theory and applications 11h15-11h35 Pedro Carvalho, Pedro Simões, Rui Cunha Marques Title: Measuring the performance of Portuguese major airports using non-parametric benchmarking frontier methods 11h35-11h55 Nuria Ramón, José L. Ruiz, Inmaculada Sirvent Title: Selecting profiles in DEA cross-efficiency evaluations 11h55-12h15 Esmeralda A. Ramalho, J.J.S. Ramalho, P.D. Henriques Title: Alternative regression models for explaining DEA efficiency scores 12h15-12h35 Clara B. Vaz, Ana S. Camanho, Rui C. Guimarães Title: The assessment of retailing efficiency using network Data Envelopment Analysis LUNCH (12h35-14h00) Session 2: Performance assessment in education 14h00-14h20 António Afonso and Miguel St. Aubyn Title: Public and private inputs in aggregate production and growth: A cross-country efficiency approach 14h20-14h40 Kristof De Witte and Mika Kortelainen Title: Blaming the exogenous environment? Conditional efficiency estimation with continuous and discrete environmental variables 14h40-15h00 Kristof De Witte and Nicky Rogge Title: Accounting for exogenous influences in a benevolent performance evaluation of teachers 15h00-15h20 Ana Isabel Martins Title: Measuring the efficiency of banks using a two-stage DEA model COFFEE BREAK (15h20-16h00) Session 3: Performance assessment of electricity distribution 16h00-16h20 Thomas Weyman-Jones, Júlia Boucinha, Catarina F. Inácio Title: Efficiency and productivity analysis in Portuguese electricity distribution networks 16h20-16h40 Vera Miguéis, Ana S. Camanho, Endre Bjørndal, Mette Bjørndal Title: Productivity change of Norwegian electricity distribution companies: A Malmquist Index analysis with restricted weights 16h40-17h00 João F.C. Sequeira, Sérgio P. Santos, Carla A.F. Amado Title: Using Data Envelopment Analysis to support the design and management of technical systems in electricity distribution 17h00-17h20 Endre Bjørndal, Mette Bjørndal, Thore Johnsen Title: Implementing super-efficiency in the regulation of electricity networks DINNER (19h30-22h30) Taylor s Port Wine Lodges. Restaurante Barão de Fladgate, Rua do Choupelo, 250, Vila Nova de Gaia 2

4 ABSTRACTS 3

5 Efficiency and productivity in higher education: An assessment of administration in universities in the United Kingdom Emmanuel Thanassoulis, Aston University, UK. The talk will cover the findings from an investigation into the costs of administration of higher education in the UK. The project was commissioned by the Higher Education Funding Council for England (2003-7) and related to an investigation of the efficiency and productivity of administrative services in UK universities. Administration accounts for a very significant proportion of expenditure in Higher Education Institutions (HEIs) in the UK. In our analysis, using data (1999/00 to 2004/5) we have found that administrative staff costs are over 40% of academic staff costs. If one takes the primary purpose of universities to be the creation and dissemination of knowledge, then clearly a substantial part of UK expenditure in higher education is directed towards support rather than mainstream activities. The project using Data Envelopment Analysis examined the scope for efficiency savings, the changes in productivity of administrative services over time and identified role model institutions on delivering cost-efficient administrative services. 4

6 Strategic responses to companies own past performance: why do some firms fare better than others? Geraint Johnes, Lancaster University Management School, UK. Jill Johnes, Lancaster University Management School, UK. Recent work on business strategy considers the evaluation of company performance using frontier methods (Devinney et al., forthcoming). The present paper build on that work to examine the extent to which company performance in one period impacts on business practices and hence performance in subsequent periods. We investigate this using a panel of annual data on some 4280 firms over the period , drawn from the Osiris data set of Bureau van Dijk. A data envelopment analysis is conducted to evaluate the efficiency of firms in converting inputs - in the form of shareholders funds, liabilities and costs - into sales. The efficiency scores are then modelled in a random parameter framework where one of the determinants of current period efficiency is the firm s own lagged efficiency. In a parsimonious model, we find that the extent to which lagged efficiency affects current efficiency varies considerably from firm to firm. Some firms maintain a relatively constant level of efficiency period after period, while the efficiency of other firms is much more variable over time. Companies with extreme values of the random parameter (either low or high) are less likely than others to have high efficiency scores. These results are used to inform a number of qualitiative case studies of companies. Our evidence suggests that firms for which the random parameter is high tend to be long established enterprises operating in narrowly and clearly defined markets, and enjoying sustained periods of market stability; firms for which the random parameter is low tend to have had a turbulent recent past involving either rapid growth (including merger activity) or decline. Meanwhile efficiency is determined in part by the industry and country with which a firm is associated, and also by the opportunities to exploit scale economies. Reference: Devinney, Timothy M., George S. Yip and Gerry Johnson (forthcoming) Using frontier analysis to analyse corporate performance, British Journal of Management. 5

7 Measuring the performance of Portuguese major Airports using Non-parametric benchmarking frontier methods Pedro Carvalho, CESUR, Instituto Superior Técnico, Universidade Técnica de Lisboa. Pedro Simões, CESUR, Instituto Superior Técnico, Universidade Técnica de Lisboa. Rui C. Marques, CESUR, Instituto Superior Técnico, Universidade Técnica de Lisboa. Airports present, as a rule, monopolistic features and a relevant market power. Thus, measuring their inefficiency is important for all stakeholders since it provides information about their economic performance. Inefficiencies are as resources which remain on the table. No one benefits from inefficiencies. This paper computes the efficiency of the Portuguese major airports using robust benchmarking non-parametric techniques. It employs data envelopment analysis (DEA) and the recent methods of bootstrap and order-m to provide robustness to the scores obtained. Therefore, the performance of Lisbon, Oporto and Faro airports are estimated using a sample of more than 100 worldwide airports. In a period of airport reform in Portugal where the building of a new airport in Lisbon, the privatization of the Portuguese airport sector and a new regulatory framework were announced, it is pertinent to evaluate the performance of the most important Portuguese airports. The results of the research are here discussed and some policy suggestions and recommendations are provided. Keywords: airports; data envelopment analysis (DEA); bootstrap; order-m; performance. 6

8 Selecting weight profiles in DEA cross-efficiency evaluations Nuria Ramón, Centro de Investigación Operativa, Universidad Miguel Hernández, Spain. José L. Ruiz, Centro de Investigación Operativa, Universidad Miguel Hernández, Spain. Inmaculada Sirvent, Centro de Investigación Operativa, Univ. Miguel Hernández, Spain. DEA cross-efficiency evaluations are based on the idea of assessing in a peer-evaluation each of the DMUs with the weights of all the units in the sample, so that the weights each unit uses to assess the remaining DMUs are selected by using some specific criteria. The traditional approaches existing in the literature use criteria that lead to a choice of weights as the result of imposing some conditions on the resulting cross-efficiency scores (see, e.g., the benevolent and the aggressive approaches). We propose to address this problem by directly acting on the choice of weights. We seek to avoid the unrealistic DEA weighting schemes that are often found in practice. To be more specific, we seek to avoid the weight profiles that are very specialized, in particular those containing zero-weights, which is an aspect of the analysis often neglected in cross-efficiency evaluations. We propose a new procedure whose use is illustrated with some numerical examples and a real-data application. 7

9 Alternative regression models for explaining DEA efficiency scores Esmeralda A. Ramalho, Departamento de Economia, Universidade de Évora. J.J.S. Ramalho, Departamento de Economia, Universidade de Évora. P.D. Henriques, Departamento de Economia, Universidade de Évora. Data envelopment analysis (DEA) is a nonparametric technique commonly used to measure the efficiency of the sampling units. Often, in a second stage, a regression model is estimated to relate DEA efficiency scores and exogenous factors. In this paper we argue that the traditional tobit approach for second stage DEA analysis does not define a reasonable data generating process for DEA scores and discuss various alternative models that may be more useful to deal with the fractional nature of DEA scores. In particular, we consider various alternative regression models appropriate to deal with fractional dependent variables, propose some generalizations to these models, and, given that DEA scores take the value 1 with a non-zero probability, examine the use of two-part models in this framework. Several tests suitable for assessing the specification of each alternative model are also discussed. Keywords: Second-stage DEA, fractional data, specification tests, one outcomes, two-part models. 8

10 The assessment of retailing efficiency using Network Data Envelopment Analysis Clara B. Vaz, Escola Superior de Tecnologia e Gestão, Instituto Politécnico de Bragança. Ana S. Camanho, Faculdade de Engenharia, Universidade do Porto. Rui C. Guimarães, Faculdade de Engenharia, Universidade do Porto. This paper describes a method for the assessment of retail store performance based on Data Envelopment Analysis (DEA). The assessment considers the stores as complex organizations that aggregate several subunits, corresponding to sections with management autonomy. This structure motivated an analysis at two different levels: the section level and the store level. The performance assessment of the sections involves a comparison among similar sections located in different stores, and evaluates efficiency spread. This is followed by an analysis at the store level to define targets for the sections. This analysis takes into account the interdependencies of the sections composing a store, as they share limited resources such as the floor area. This is achieved using a Network DEA model, which determines the maximum store sales allowing for reallocations of area among the sections within a store. The method developed is illustrated using a case study consisting of a Portuguese chain of supermarkets. 9

11 Public and Private Inputs in Aggregate Production and Growth: A Cross-country Efficiency Approach António Afonso, Instituto Superior de Economia e Gestão, Univ. Técnica de Lisboa Miguel St. Aubyn, Instituto Superior de Economia e Gestão, Univ. Técnica de Lisboa In a cross section of OECD countries we replace the macroeconomic production function by a production possibility frontier, being TFP the composite effect of efficiency scores and possibility frontier changes. We consider, for the periods 1970, 1980, 1990, 2000, one output: GDP per worker; three inputs: human capital, public physical capital per worker and private physical per worker. We use a semi-parametric analysis, computing Malmquist productivity indexes, and we also resort to stochastic frontier analysis. Results show that private capital is more important for growth, although public and human capital also contribute positively. A governance indicator, a non-discretionary input, explains inefficiency. Non-parametric and parametric results coincide rather closely on the countries movements vis-à-vis the possibility frontier, and on their relative distances to the frontier. Keywords: economic growth, public spending, efficiency, Malmquist index. 10

12 Blaming the exogenous environment? Conditional efficiency estimation with continuous and discrete environmental variables Kristof De Witte, Catholic Univ. of Leuven, Belgium, and Maastricht Univ, Netherlands. Mika Kortelainen, University of Manchester, UK. The literature counts various approaches to incorporate the exogenous environment in nonparametric efficiency analysis. In this paper, we focus on the conditional efficiency model of Cazals et al. (2002) and Daraio and Simar (2005, 2007). The approach starts from the probabilistic formulation of the production process and incorporates the operational environment by conditioning on the exogenous characteristics. This conditional efficiency approach generalizes the traditional nonparametric approaches by avoiding the separability condition and by not requiring any specification on the direction of influence of exogenous variables. This paper focuses on three issues. Firstly, it considers the inclusion of both discrete and continuous exogenous variables in the conditional efficiency framework. This paper shows how to adapt the nonparametric conditional efficiency measures to include mixed (i.e. both continuous and discrete) exogenous variables by specifying an appropriate kernel function which smoothes the mixed variables. In doing so, we propose a procedure to estimate kernel bandwidths both for continuous and discrete variables. Secondly, we argue and show that our approach can include a number of ordered and/or unordered categorical variables along with continuous exogenous variables even in relatively small samples. We show that the dimensionality problem is not the case for discrete exogenous variables with compact support. Thirdly, we present a framework to test nonparametrically the significance of the exogenous variables. We extend the Daraio and Simar toolbox for visualizing the effects of the continuous exogenous variables to a generalized setting which allows both visualization and statistical inference of continuous and discrete exogenous variables. For the significance testing, we use recently developed nonparametric bootstrap-based procedures. To illustrate our approach, we consider a couple of simulation scenarios that are similar to scenarios already used in the literature. In addition, we illustrate the approach by assessing the efficiency of a random sample of British 15 years old pupils (based on the PISA data set). 11

13 Accounting for exogenous influences in a benevolent performance evaluation of teachers Kristof De Witte, Catholic University of Leuven, Belgium Nicky Rogge, Hogeschool-Universiteit Brussel, Centre for Economics & Management, Brussels, Belgium Students evaluations of teacher performance (SETs) are increasingly used by universities and colleges for teaching improvement and decision making (e.g., promotion or tenure). However, SETs are highly controversial mainly due to two issues: (1) teachers value various aspects of excellent teaching differently, and, to be fair, (2) SETs should be determined solely by the teacher s actual performance in the classroom, not by other influences (related to the teacher, the students or the course) which are not under his or her control. To account for these two issues, this paper constructs SETs using a specially tailored version of the popular non-parametric Data Envelopment Analysis (DEA) approach. In particular, in a so-called Benefit of the doubt model we account for different values and interpretations that teachers attach to good teaching. Within this model, we reduce the impact of measurement errors and a-typical observations, and account explicitly for heterogeneous background characteristics arising from teacher, student and course characteristics. To show the potentiality of the method, we examine teacher performance for the Hogeschool Universiteit Brussel (located in Belgium). Our findings suggest that heterogeneous background characteristics play an important role in teacher performance. Keywords: Teacher performance, Data envelopment analysis, Conditional efficiency, Education. 12

14 Measuring the efficiency of banks using a two-stage DEA model Ana Isabel Martins, Escola Superior de Gestão, Hotelaria e Turismo, U. Algarve. Currently facing the biggest world-wide crisis of the last 30 years, significant losses in revenues are foreseen for the banking sector as well as an increasing competitive pressure, which may lead to lower margins and to the increase of efficiency in order to maintain market share. Using data from 2007, the efficiency of the 37 major banks operating in Portugal is evaluated through DEA methodology. We present a two-stage model for evaluating the efficiency, specific to the banking sector, which allows to circumvent the problem of the two existing approaches (Production/Intermediation) and incorporate variables that reflect profitability, value creation and opportunity cost to shareholders. It is intended to overcome the main problem associated with the banking sector, particularly regarding the classification of deposits. While in the approach based on production deposits are considered outputs, in the approach based on the intermediation deposits are considered inputs. In such cases, typically two-stage processes, it is usual to apply standard DEA models to each stage. However, such an approach may conclude that two inefficient stages lead to an overall efficient DMU with the inputs of the first stage and outputs of the second stage. The distortion/improvement in the DEA frontier is caused by the presence of intermediate measures. The efficiency is analyzed using a global perspective that includes all the banks, assuming that all have access to the same technology. Subsequent analysis is made to the efficiency by groups based on homogeneity and risk factors, estimated separate frontiers, analyzed the inefficiencies intra-groups and the differences between the groups. 13

15 Efficiency and Productivity Analysis in Portuguese Electricity Distribution Networks Thomas Weyman-Jones, Department of Economics, Loughborough University, UK. Júlia Boucinha, EDP, Lisboa Catarina F. Inácio, EDP, Lisboa Frontier methods are very useful tools for benchmarking network activities of regulated companies. Following a brief description of the Portuguese electricity distribution company performance in the recent past, this paper illustrates the application of Data Envelopment Analysis (DEA) to evaluate the company s productivity over the last 10 years. DEA and parametric methods (SFA) have also been used to evaluate the efficiency levels of the different networks within the company. The paper shows how these analyses have been used by the regulator, in order to determine the company s overall efficiency underlying the determination of allowed revenues for the two last regulatory periods. 14

16 Productivity change of Norwegian electricity distribution companies: a Malmquist index analysis with restricted weights Vera Miguéis, Faculdade de Engenharia, Universidade do Porto Ana Camanho, Faculdade de Engenharia, Universidade do Porto Endre Bjørndal, Norwegian School of Economics and Business Administration, Bergen. Mette Bjørndal, Norwegian School of Economics and Business Administration, Bergen. In the electricity sector regulators aim to insure the reasonableness of the distributing prices. Therefore the characteristics of appropriate regulatory models have been extensively studied and, as a result, a variety of approaches to incentive regulation have been adopted. Most regulators have moved away from traditional rate of return regulation to benchmarking models based on frontier techniques. Norwegian regulatory models are amongst the most sophisticated approaches for regulation. Norwegian electricity distribution companies are regulated by means of a yardstick model in which the cost norms are calculated based on relative efficiency scores obtained by Data Envelopment Analysis (DEA). The model currently used has one input (total cost) and several outputs rep- resenting direct measures of the production activity (transported energy and customers), the structural conditions and the geographic context (forest, snow and coast). In this model, large differences in shadow prices of outputs between companies have been noticed. In addition, there seems to be a tendency for higher efficiency scores being associated to companies with high weights on geographic factors instead of weighting outputs representing the production activity (i.e. energy delivered or customers served). This is unreasonable, and so the objective of this paper is to restrict the weights (shadow prices) of the DEA model for the geographic outputs. This paper discusses the incorporation of virtual weight restrictions for geography variables in the Malmquist index. It measures the change in efficiency and the technological change observed in the companies, which enables testing if the regulatory objective of productivity improvement over time was achieved. This analysis reveals the performance path of the companies over time, such that it is possible to identify the innovators, i.e. the companies that are pushing the production possibility set to more productive levels over time. 15

17 Using Data Envelopment Analysis to support the design and management of technical systems in electricity distribution João F.C. Sequeira, EDP Distribuição, Lisboa. Sérgio P. Santos, Faculdade de Economia da Universidade do Algarve. Carla A.F. Amado, Faculdade de Economia da Universidade do Algarve. Data envelopment analysis (DEA) has been extensively used to assess efficiency at an organizational level. Comparatively, its use as a management tool to enhance the design and the performance of technical systems has been scarce. This paper has two aims. The first aim is to develop an integrated DEA based performance measurement system to compare the efficiency of electricity distribution lines and the second aim is to study the factors that influence the efficiency of the lines. By studying in detail the input-output transformation box, this paper intends to contribute to develop an understanding regarding the technologies, processes, structures and procedures that contribute to best practice in the systems of electricity distribution. Keywords: Performance assessment, Data Envelopment Analysis, Electricity distribution. 16

18 Implementing Super-Efficiency in the Regulation of Electricity Networks Endre Bjørndal, Norwegian School of Economics and Business Administration, Bergen. Mette Bjørndal, Norwegian School of Economics and Business Administration, Bergen. Thore Johnsen, Norwegian School of Economics and Business Administration, Bergen. A principal objective of the regulation is to give incentives for cost efficiency in operations and investments, including to facilitate the best possible organization of individual companies and the industry in total. In an ideal market, with perfect competition, the company s revenues are determined by the cost of the marginal player of the industry, adjusted for differences in volume and product quality. The company s relative efficiency and costs will then determine the profitability of the company. This is perhaps the most important characteristic of an industry that is disciplined by the competitive forces; a company cannot shift company-specific costs on to its customers, on the other hand, it will retain the advantage of being more efficient and having lower than representative costs. Similarly, a company will be punished for or rewarded for providing, respectively, worse than or better than representative product quality. The market pays for what is produced, irrespective of how it is produced, for instance with respect to company costs, the age of the production equipment, and how operations are organized, whether outsourced or kept within the company. Another characteristic of a competitive industry is the continual differences in efficiency levels within the industry, so that the average, and not the best, efficiency level determines the competitive return on invested capital. Companies that are especially efficient may generate lasting super-profits, while inefficient companies will fail to meet the requirements, and may be dissolved, restructured or bought by the more efficient players. Continual efficiency and profitability differences will be reflected in corresponding differences in the market s pricing of the companies of equity, i.e. the equity of very efficient companies will have a high market price compared to the book value, and the opposite for very inefficient companies. In this paper we consider how to implement super-efficiency in a regulation model for electricity companies. In this model, the cost norms are based on DEA cost efficiency estimates. One way of introducing super-efficiency is to measure a DMU s cost efficiency based on the other companies cost and output data only, i.e. excluding the DMU s own observations from the data set. However, further calibration of the total industry cost norm is necessary in order to ensure that companies with average efficiency earn the regulatory rate of return. We use data for Norwegian distribution and regional transmission companies in our analyses. 17

19 LIST OF PARTICIPANTS 18

20 Abraão Luís Henriques da Silva Instituto Superior de Contabilidade e Administração de Coimbra (ISCAC) Quinta Agrícola, Bencata Coimbra lsilva@iscac.pt Alberto Castro Universidade Católica Portuguesa Rua Diogo Botelho, Porto acastro@porto.ucp.pt Ana Isabel Rita Martins Escola Superior de Gestão, Hotelaria e Turismo Universidade do Algarve aimartin@ualg.pt Catarina Féteira Inácio EDP R. Camilo Castelo Branco, 43-5 o Lisboa catarinafeteira.inacio@edp.pt Diogo Borges Universidade Católica Portuguesa Rua Diogo Botelho, Porto ei04016@fe.up.pt Emmanuel Thanassoulis Aston Business School Aston Triangle, Birmingham B4 7ET United Kingdom e.thanassoulis@aston.ac.uk Ana Maria S. Camanho Faculdade de Engenharia, U. Porto Rua Dr. Roberto Frias Porto acamanho@fe.up.pt António Afonso ISEG/UTL Rua Miguel Lupi, Lisboa aafonso@iseg.utl.pt Carla Alexandra Filipe Amado Univ. Algarve - Faculdade de Economia Campus de Gambelas Faro camado@ualg.pt Endre Bjørndal Norwegian School Economics and Business Administration Helleveien 30 NO-5045 Bergen, Norway Endre.Bjorndal@nhh.no Esmeralda de Jesus A. Ramalho Departamento de Economia, U. Évora Largo dos Colegiais, Évora, Portugal ela@uevora.pt Fernando Pedro Sarre Rua do Calvário Residências do Pátio, 2 o Dt Almancil 19

21 Geraint Johnes Lancaster University Management School Lancaster LA1 4YX United Kingdom Inmaculada Sirvent Quílez Centro de Investigación Operativa, Universidad Miguel Hernández, Avd. de la Universidad, s/n Elche (Alicante), Spain Joana Hora Faculdade de Engenharia, U. Porto Rua Dr. Roberto Frias Porto José Luis Ruiz Gómez Centro de Investigación Operativa, Universidad Miguel Hernández, Avd. de la Universidad, s/n Elche (Alicante), Spain Kristof De Witte University of Leuven, Naamsestraat 69, 3000 Leuven; and Belgium Maastricht University, Kapoenstraat 23, 6200 MD Maastricht, Netherlands Luísa Tavares Faculdade de Engenharia, U. Porto, Rua Dr. Roberto Frias Porto Maria Clara R. Bento Vaz Fernandes Instituto Politécnico de Bragança - ESTG Cruzamento de Smil Bragança clvaz@ipb.pt Maria Conceição Silva Portela Universidade Católica Portuguesa, Rua Diogo Botelho, Porto csilva@porto.ucp.pt João Falcão e Cunha Faculdade de Engenharia do Porto Rua Dr. Roberto Frias Porto, Portugal jfcunha@fe.up.pt Miguel St. Aubyn ISEG/UTL Rua Miguel Lupi, Lisboa mstaubyn@iseg.utl.pt Júlia Mendonça Boucinha EDP R. Camilo Castelo Branco, 43-5 o Lisboa julia.boucinha@edp.pt Nicky Rogge Katholieke Universiteit Leuven Naamsestraat Leuven, Belgium Nicky.Rogge@econ.kuleuven.be 20

22 Nuria Ramon Escolano Centro de Investigación Operativa, Universidad Miguel Hernández, Avd. de la Universidad, s/n Elche (Alicante), Spain Pedro Tiago C. Carvalho CESUR, Instituto Superior Técnico, Av. Rovisco Pais, Lisboa Pedro Tiago Simões CESUR, Instituto Superior Técnico, Av. Rovisco Pais, Lisboa Rui Cunha Marques CESUR, Instituto Superior Técnico, Av. Rovisco Pais, Lisboa Sofia Nogueira da Silva Universidade Católica Portuguesa, Rua Diogo Botelho, Porto Vera Miguéis Faculdade de Engenharia, U. Porto, Rua Dr. Roberto Frias Porto Ricardo Gonçalves Universidade Católica Portuguesa, Rua Diogo Botelho, Porto 21

23 Organising Committee: Maria Conceição Portela Faculdade de Economia e Gestão Universidade Católica Portuguesa Rua Diogo Botelho, Porto, Portugal csilva@porto.ucp.pt Ana Maria Camanho Dep. Engenharia Industrial e Gestão Faculdade de Engenharia Universidade do Porto Rua Dr. Roberto Frias Porto acamanho@fe.up.pt 22