Documents disponibles écrits par cet auteur

An improvement on the Tracy and Chen model / M. Khalili in Journal of the operational research society (JORS), Vol. 61 N° 12 (Décembre 2010) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 61 N° 12 (Décembre 2010) . - pp. 1789–1793 Titre : An improvement on the Tracy and Chen model : a generalized model for weight restrictions in DEA Type de document : texte imprimé Auteurs : M. Khalili, Auteur ; A. S. Camanho, Auteur ; M. C. A. S. Portela, Auteur Année de publication : 2011 Article en page(s) : pp. 1789–1793 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Data  envelopment  analysis  Relative  efficiency  Generalized  weight  restrictions Index. décimale : 001.424 Résumé : Recently Tracy and Chen presented a parametric DEA model (PDEA) to assess relative efficiency in the presence of a generalized form of linear weight restrictions. This paper proposes a modification to the PDEA model that avoids the need to resort to searching algorithms to estimate efficiency, and assures that the correct efficiency scores are obtained in a single stage using mathematical programming solvers. The results of this model and the results of Tracy and Chen's PDEA model are compared using the examples reported in their paper. The results confirm the superiority of the model proposed in this paper. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n12/abs/jors2009140a.html [article] An improvement on the Tracy and Chen model : a generalized model for weight restrictions in DEA [texte imprimé] / M. Khalili, Auteur ; A. S. Camanho, Auteur ; M. C. A. S. Portela, Auteur . - 2011 . - pp. 1789–1793. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 61 N° 12 (Décembre 2010) . - pp. 1789–1793 Mots-clés : Data  envelopment  analysis  Relative  efficiency  Generalized  weight  restrictions Index. décimale : 001.424 Résumé : Recently Tracy and Chen presented a parametric DEA model (PDEA) to assess relative efficiency in the presence of a generalized form of linear weight restrictions. This paper proposes a modification to the PDEA model that avoids the need to resort to searching algorithms to estimate efficiency, and assures that the correct efficiency scores are obtained in a single stage using mathematical programming solvers. The results of this model and the results of Tracy and Chen's PDEA model are compared using the examples reported in their paper. The results confirm the superiority of the model proposed in this paper. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n12/abs/jors2009140a.html

Analysis of complementary methodologies for the estimation of school value added / M. C. A. S. Portela in Journal of the operational research society (JORS), Vol. 61 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 61 N° 7 (Juillet 2010) . - pp. 1122–1132 Titre : Analysis of complementary methodologies for the estimation of school value added Type de document : texte imprimé Auteurs : M. C. A. S. Portela, Auteur ; A. S. Camanho, Auteur Année de publication : 2011 Article en page(s) : pp. 1122–1132 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Efficiency  DEA  Value  added  Secondary  schools Index. décimale : 001.424 Résumé : This paper analyses the value added (VA) of a sample of Portuguese schools using two methodologies: data envelopment analysis (DEA) and the methodology used presently by the UK Department for Children, Schools and Families (DCSF). The VA estimates obtained by the two methods are substantially different. This reflects their different focus: DEA emphasizes on best-observed performance, whereas the DCSF method reveals average performance. The main advantage of the methodology used by the DCSF is its simplicity, although it confounds pupil effects with school effects in the estimation of school VA. In contrast, the DEA methodology can differentiate these effects, but the complexity may prevent its use in a systematic way. This paper shows that the two methods provide complementary information regarding the VA of schools, and their joint use can improve the understanding of the relative effectiveness of schools regarding the progress that pupils make between educational stages. DEWEY : 001.424 ISSN : 0361-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n7/abs/jors200985a.html [article] Analysis of complementary methodologies for the estimation of school value added [texte imprimé] / M. C. A. S. Portela, Auteur ; A. S. Camanho, Auteur . - 2011 . - pp. 1122–1132. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 61 N° 7 (Juillet 2010) . - pp. 1122–1132 Mots-clés : Efficiency  DEA  Value  added  Secondary  schools Index. décimale : 001.424 Résumé : This paper analyses the value added (VA) of a sample of Portuguese schools using two methodologies: data envelopment analysis (DEA) and the methodology used presently by the UK Department for Children, Schools and Families (DCSF). The VA estimates obtained by the two methods are substantially different. This reflects their different focus: DEA emphasizes on best-observed performance, whereas the DCSF method reveals average performance. The main advantage of the methodology used by the DCSF is its simplicity, although it confounds pupil effects with school effects in the estimation of school VA. In contrast, the DEA methodology can differentiate these effects, but the complexity may prevent its use in a systematic way. This paper shows that the two methods provide complementary information regarding the VA of schools, and their joint use can improve the understanding of the relative effectiveness of schools regarding the progress that pupils make between educational stages. DEWEY : 001.424 ISSN : 0361-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n7/abs/jors200985a.html

Performance assessment of secondary schools / M. C. S. Portela in Journal of the operational research society (JORS), Vol. 63 N° 8 (Août 2012) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 63 N° 8 (Août 2012) . - pp. 1098–1115 Titre : Performance assessment of secondary schools : the snapshot of a country taken by DEA Type de document : texte imprimé Auteurs : M. C. S. Portela, Auteur ; A. S. Camanho, Auteur ; D. Borges, Auteur Année de publication : 2012 Article en page(s) : pp. 1098–1115 Note générale : Operational research Langues : Anglais (eng) Mots-clés : Data  envelopment  analysis  Secondary  schools  Weight  restrictions  Single  weights Index. décimale : 001.424 Résumé : This paper describes a performance assessment of Portuguese secondary schools using data envelopment analysis (DEA). The assessment adopts a perspective where schools are viewed as promoting students achievement given their characteristics in terms of academic abilities and socio-economic background. Our sample comprised all secondary schools in Portugal with both basic and secondary education levels. Two types of DEA analysis are performed: one using an output-oriented model that restricts output (exam scores) weights to be linked to the number of students that have done that exam in the school, and the other using a model that restricts factor weights to be equal for all schools. In this model the weight restrictions are linked to the total number of exams done nationally. The first model is well suited for identifying worst performing schools and to assess schools that may specialize in certain subjects, whereas the latter is best suited for improving discrimination between best performing schools when pursuing the identification of benchmarks, as well as to construct performance rankings. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v63/n8/abs/jors2011114a.html [article] Performance assessment of secondary schools : the snapshot of a country taken by DEA [texte imprimé] / M. C. S. Portela, Auteur ; A. S. Camanho, Auteur ; D. Borges, Auteur . - 2012 . - pp. 1098–1115. Operational research Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 63 N° 8 (Août 2012) . - pp. 1098–1115 Mots-clés : Data  envelopment  analysis  Secondary  schools  Weight  restrictions  Single  weights Index. décimale : 001.424 Résumé : This paper describes a performance assessment of Portuguese secondary schools using data envelopment analysis (DEA). The assessment adopts a perspective where schools are viewed as promoting students achievement given their characteristics in terms of academic abilities and socio-economic background. Our sample comprised all secondary schools in Portugal with both basic and secondary education levels. Two types of DEA analysis are performed: one using an output-oriented model that restricts output (exam scores) weights to be linked to the number of students that have done that exam in the school, and the other using a model that restricts factor weights to be equal for all schools. In this model the weight restrictions are linked to the total number of exams done nationally. The first model is well suited for identifying worst performing schools and to assess schools that may specialize in certain subjects, whereas the latter is best suited for improving discrimination between best performing schools when pursuing the identification of benchmarks, as well as to construct performance rankings. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v63/n8/abs/jors2011114a.html

Performance comparison of retailing stores using a Malmquist-type index / C. B. Vaz in Journal of the operational research society (JORS), Vol. 63 N° 5 (Mai 2012) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 63 N° 5 (Mai 2012) . - pp. 631–645 Titre : Performance comparison of retailing stores using a Malmquist-type index Type de document : texte imprimé Auteurs : C. B. Vaz, Auteur ; A. S. Camanho, Auteur Année de publication : 2012 Article en page(s) : pp. 631–645 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Data  envelopment  analysis  Retail  Efficiency  Productivity  Malmquist  index  Statistical  tests Index. décimale : 001.424 Résumé : This study develops a framework that combines different management science methods to provide insights concerning the performance of retailing stores. First, the framework enables to specify appropriate targets for stores of a retail network using data envelopment analysis. This involves comparing stores within homogenous groups, that is, supermarkets and hypermarkets. Second, the framework compares the overall performance of these two groups. This requires the combined use of a Malmquist-type index and statistical tests. This index is decomposed into sub-indices for comparing the differences between groups in terms of the efficiency spread in each group of stores and the productivity differences between the best-practice frontiers spanned by the benchmark stores from each group. The hypothesis tests are used to verify if the differences between groups captured by the sub-indices are statistically significant. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v63/n5/abs/jors201163a.html [article] Performance comparison of retailing stores using a Malmquist-type index [texte imprimé] / C. B. Vaz, Auteur ; A. S. Camanho, Auteur . - 2012 . - pp. 631–645. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 63 N° 5 (Mai 2012) . - pp. 631–645 Mots-clés : Data  envelopment  analysis  Retail  Efficiency  Productivity  Malmquist  index  Statistical  tests Index. décimale : 001.424 Résumé : This study develops a framework that combines different management science methods to provide insights concerning the performance of retailing stores. First, the framework enables to specify appropriate targets for stores of a retail network using data envelopment analysis. This involves comparing stores within homogenous groups, that is, supermarkets and hypermarkets. Second, the framework compares the overall performance of these two groups. This requires the combined use of a Malmquist-type index and statistical tests. This index is decomposed into sub-indices for comparing the differences between groups in terms of the efficiency spread in each group of stores and the productivity differences between the best-practice frontiers spanned by the benchmark stores from each group. The hypothesis tests are used to verify if the differences between groups captured by the sub-indices are statistically significant. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v63/n5/abs/jors201163a.html

Productivity change and innovation in Norwegian electricity distribution companies / V. L. Miguéis in Journal of the operational research society (JORS), Vol. 63 N° 7 (Juillet 2012) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 63 N° 7 (Juillet 2012) . - pp. 982–990 Titre : Productivity change and innovation in Norwegian electricity distribution companies Type de document : texte imprimé Auteurs : V. L. Miguéis, Auteur ; A. S. Camanho, Auteur ; E. Bjørndal, Auteur ; M. Bjørndal, Auteur Année de publication : 2012 Article en page(s) : pp. 982–990 Note générale : Operational research Langues : Anglais (eng) Mots-clés : Data  envelopment  analysis  Regulation  Electricity  distribution  Malmquist  index  Virtual  weight  restrictions Index. décimale : 001.424 Résumé : Regulators of electricity distribution networks have typically applied Data Envelopment Analysis (DEA) to cross-section data for benchmarking purposes. However, the use of panel data to analyse the impact of regulatory policies on productivity change over time is less frequent. The main purpose of this paper is to construct a Malmquist productivity index to examine the recent productivity change experienced by Norwegian distribution companies between 2004 and 2007. The Malmquist index is decomposed in order to explore the sources of productivity change, and to identify the innovator companies that pushed the frontier forward each year. The input and output variables considered are those used by the Norwegian regulator. In order to reflect appropriately the exogenous conditions where the companies operate, the efficiency model used in this paper incorporates geography variables as outputs of the DEA model. Unlike the model used by the regulator, we included virtual weight restrictions in the DEA formulation to correct the biases in the DEA results that may be associated to a judicious choice of weights by some of the companies. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v63/n7/abs/jors201182a.html [article] Productivity change and innovation in Norwegian electricity distribution companies [texte imprimé] / V. L. Miguéis, Auteur ; A. S. Camanho, Auteur ; E. Bjørndal, Auteur ; M. Bjørndal, Auteur . - 2012 . - pp. 982–990. Operational research Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 63 N° 7 (Juillet 2012) . - pp. 982–990 Mots-clés : Data  envelopment  analysis  Regulation  Electricity  distribution  Malmquist  index  Virtual  weight  restrictions Index. décimale : 001.424 Résumé : Regulators of electricity distribution networks have typically applied Data Envelopment Analysis (DEA) to cross-section data for benchmarking purposes. However, the use of panel data to analyse the impact of regulatory policies on productivity change over time is less frequent. The main purpose of this paper is to construct a Malmquist productivity index to examine the recent productivity change experienced by Norwegian distribution companies between 2004 and 2007. The Malmquist index is decomposed in order to explore the sources of productivity change, and to identify the innovator companies that pushed the frontier forward each year. The input and output variables considered are those used by the Norwegian regulator. In order to reflect appropriately the exogenous conditions where the companies operate, the efficiency model used in this paper incorporates geography variables as outputs of the DEA model. Unlike the model used by the regulator, we included virtual weight restrictions in the DEA formulation to correct the biases in the DEA results that may be associated to a judicious choice of weights by some of the companies. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v63/n7/abs/jors201182a.html