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Selecting slacks-based data envelopment analysis models

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  • Toloo, Mehdi
  • Tone, Kaoru
  • Izadikhah, Mohammad

Abstract

Data envelopment analysis (DEA) is a well-known data-driven mathematical modeling approach that aims at evaluating the relative efficiency of a set of comparable decision making units (DMUs) with multiple inputs and multiple outputs. The number of inputs and outputs (performance factors) plays a vital role for successful applications of DEA. There is a statistical and empirical rule in DEA that if the number of performance factors is high in comparison with the number of DMUs, then a large percentage of the units will be determined as efficient, which is questionable and unacceptable in the performance evaluation context. However, in some real-world applications, the number of performance factors is relatively larger than the number of DMUs. To cope with this issue, selecting models have been developed to select a subset of performance factors that lead to acceptable results.

Suggested Citation

  • Toloo, Mehdi & Tone, Kaoru & Izadikhah, Mohammad, 2023. "Selecting slacks-based data envelopment analysis models," European Journal of Operational Research, Elsevier, vol. 308(3), pages 1302-1318.
  • Handle: RePEc:eee:ejores:v:308:y:2023:i:3:p:1302-1318
    DOI: 10.1016/j.ejor.2022.12.032
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    as
    1. Phillip Fanchon, 2003. "Variable selection for dynamic measures of efficiency in the computer industry," International Advances in Economic Research, Springer;International Atlantic Economic Society, vol. 9(3), pages 175-188, August.
    2. Geromichalos, Athanasios & Simonovska, Ina, 2014. "Asset liquidity and international portfolio choice," Journal of Economic Theory, Elsevier, vol. 151(C), pages 342-380.
    3. Arabi, Behrouz & Munisamy, Susila & Emrouznejad, Ali & Toloo, Mehdi & Ghazizadeh, Mohammad Sadegh, 2016. "Eco-efficiency considering the issue of heterogeneity among power plants," Energy, Elsevier, vol. 111(C), pages 722-735.
    4. Golany, B & Roll, Y, 1989. "An application procedure for DEA," Omega, Elsevier, vol. 17(3), pages 237-250.
    5. Toloo, Mehdi & Hančlová, Jana, 2020. "Multi-valued measures in DEA in the presence of undesirable outputs," Omega, Elsevier, vol. 94(C).
    6. Tone, Kaoru & Chang, Tsung-Sheng & Wu, Chen-Hui, 2020. "Handling negative data in slacks-based measure data envelopment analysis models," European Journal of Operational Research, Elsevier, vol. 282(3), pages 926-935.
    7. Per Andersen & Niels Christian Petersen, 1993. "A Procedure for Ranking Efficient Units in Data Envelopment Analysis," Management Science, INFORMS, vol. 39(10), pages 1261-1264, October.
    8. Itemgenova, Aigerim & Sikveland, Marius, 2020. "The determinants of the price-earnings ratio in the Norwegian aquaculture industry," Journal of Commodity Markets, Elsevier, vol. 17(C).
    9. Mehdi Toloo & Mona Barat & Atefeh Masoumzadeh, 2015. "Selective measures in data envelopment analysis," Annals of Operations Research, Springer, vol. 226(1), pages 623-642, March.
    10. Inmaculada Sirvent & José L. Ruiz & Fernando Borrás & Jesús T. Pastor, 2005. "A Monte Carlo Evaluation Of Several Tests For The Selection Of Variables In Dea Models," International Journal of Information Technology & Decision Making (IJITDM), World Scientific Publishing Co. Pte. Ltd., vol. 4(03), pages 325-343.
    11. Wilson, Paul W., 2018. "Dimension reduction in nonparametric models of production," European Journal of Operational Research, Elsevier, vol. 267(1), pages 349-367.
    12. Adler, Nicole & Golany, Boaz, 2001. "Evaluation of deregulated airline networks using data envelopment analysis combined with principal component analysis with an application to Western Europe," European Journal of Operational Research, Elsevier, vol. 132(2), pages 260-273, July.
    13. Merja Halme & Tarja Joro & Pekka Korhonen & Seppo Salo & Jyrki Wallenius, 1999. "A Value Efficiency Approach to Incorporating Preference Information in Data Envelopment Analysis," Management Science, INFORMS, vol. 45(1), pages 103-115, January.
    14. Boisjoly, Russell P. & Conine, Thomas E. & McDonald, Michael B., 2020. "Working capital management: Financial and valuation impacts," Journal of Business Research, Elsevier, vol. 108(C), pages 1-8.
    15. Cepec, Jaka & Grajzl, Peter, 2020. "Debt-to-equity conversion in bankruptcy reorganization and post-bankruptcy firm survival," International Review of Law and Economics, Elsevier, vol. 61(C).
    16. Fuhrer, Lucas Marc & Müller, Benjamin & Steiner, Luzian, 2017. "The Liquidity Coverage Ratio and security prices," Journal of Banking & Finance, Elsevier, vol. 75(C), pages 292-311.
    17. Victor Podinovski & Emmanuel Thanassoulis, 2007. "Improving discrimination in data envelopment analysis: some practical suggestions," Journal of Productivity Analysis, Springer, vol. 28(1), pages 117-126, October.
    18. Liu, Shuyan & Jia, Ruo & Zhao, Yulong & Sun, Qixiang, 2019. "Global consistent or market-oriented? A quantitative assessment of RBC standards, solvency II, and C-ROSS," Pacific-Basin Finance Journal, Elsevier, vol. 57(C).
    19. Sudarsanam, P. S. & Taffler, R. J., 1995. "Financial ratio proportionality and inter-temporal stability: An empirical analysis," Journal of Banking & Finance, Elsevier, vol. 19(1), pages 45-60, April.
    20. Lim, Sungmook & Oh, Kwang Wuk & Zhu, Joe, 2014. "Use of DEA cross-efficiency evaluation in portfolio selection: An application to Korean stock market," European Journal of Operational Research, Elsevier, vol. 236(1), pages 361-368.
    21. Charnes, A. & Cooper, W. W. & Huang, Z. M. & Sun, D. B., 1990. "Polyhedral Cone-Ratio DEA Models with an illustrative application to large commercial banks," Journal of Econometrics, Elsevier, vol. 46(1-2), pages 73-91.
    22. Cont, Rama & Kotlicki, Artur & Valderrama, Laura, 2020. "Liquidity at risk: Joint stress testing of solvency and liquidity," Journal of Banking & Finance, Elsevier, vol. 118(C).
    23. Nguyen, Duc Khuong & Vo, Dinh-Tri, 2020. "Enterprise risk management and solvency: The case of the listed EU insurers," Journal of Business Research, Elsevier, vol. 113(C), pages 360-369.
    24. Hibbert, Ann Marie & Kang, Qiang & Kumar, Alok & Mishra, Suchi, 2020. "Heterogeneous beliefs and return volatility around seasoned equity offerings," Journal of Financial Economics, Elsevier, vol. 137(2), pages 571-589.
    25. Miyazato, Naomi, 2010. "The optimal size of Japan's public pensions: An analysis considering the risks of longevity and volatility of return on assets," Japan and the World Economy, Elsevier, vol. 22(1), pages 31-39, January.
    26. Podinovski, Victor V. & Bouzdine-Chameeva, Tatiana, 2016. "On single-stage DEA models with weight restrictions," European Journal of Operational Research, Elsevier, vol. 248(3), pages 1044-1050.
    27. Chen, Chailin & Cook, Wade D. & Imanirad, Raha & Zhu, Joe, 2020. "Balancing Fairness and Efficiency: Performance Evaluation with Disadvantaged Units in Non-homogeneous Environments," European Journal of Operational Research, Elsevier, vol. 287(3), pages 1003-1013.
    28. Peyrache, Antonio & Rose, Christiern & Sicilia, Gabriela, 2020. "Variable selection in Data Envelopment Analysis," European Journal of Operational Research, Elsevier, vol. 282(2), pages 644-659.
    29. Saranga, Haritha, 2009. "The Indian auto component industry - Estimation of operational efficiency and its determinants using DEA," European Journal of Operational Research, Elsevier, vol. 196(2), pages 707-718, July.
    30. Lewellen, Jonathan, 2004. "Predicting returns with financial ratios," Journal of Financial Economics, Elsevier, vol. 74(2), pages 209-235, November.
    31. Charnes, A. & Cooper, W. W. & Rhodes, E., 1978. "Measuring the efficiency of decision making units," European Journal of Operational Research, Elsevier, vol. 2(6), pages 429-444, November.
    32. John Ruggiero, 2005. "Impact Assessment Of Input Omission On Dea," International Journal of Information Technology & Decision Making (IJITDM), World Scientific Publishing Co. Pte. Ltd., vol. 4(03), pages 359-368.
    33. Jesús T. Pastor & JosÉ L. Ruiz & Inmaculada Sirvent, 2002. "A Statistical Test for Nested Radial Dea Models," Operations Research, INFORMS, vol. 50(4), pages 728-735, August.
    34. Jahangoshai Rezaee, Mustafa & Jozmaleki, Mehrdad & Valipour, Mahsa, 2018. "Integrating dynamic fuzzy C-means, data envelopment analysis and artificial neural network to online prediction performance of companies in stock exchange," Physica A: Statistical Mechanics and its Applications, Elsevier, vol. 489(C), pages 78-93.
    35. Joe Zhu, 2014. "DEA Cross Efficiency," International Series in Operations Research & Management Science, in: Quantitative Models for Performance Evaluation and Benchmarking, edition 3, chapter 4, pages 61-92, Springer.
    36. Nataraja, Niranjan R. & Johnson, Andrew L., 2011. "Guidelines for using variable selection techniques in data envelopment analysis," European Journal of Operational Research, Elsevier, vol. 215(3), pages 662-669, December.
    37. Lam, Keith S. K., 2002. "The relationship between size, book-to-market equity ratio, earnings-price ratio, and return for the Hong Kong stock market," Global Finance Journal, Elsevier, vol. 13(2), pages 163-179.
    38. Pastor, J. T. & Ruiz, J. L. & Sirvent, I., 1999. "An enhanced DEA Russell graph efficiency measure," European Journal of Operational Research, Elsevier, vol. 115(3), pages 596-607, June.
    39. Eun, Cheol S. & Lee, Jinsoo, 2010. "Evolution of earnings-to-price ratios: International evidence," Global Finance Journal, Elsevier, vol. 21(2), pages 125-137.
    40. N Adler & B Golany, 2002. "Including principal component weights to improve discrimination in data envelopment analysis," Journal of the Operational Research Society, Palgrave Macmillan;The OR Society, vol. 53(9), pages 985-991, September.
    41. Chang, Seong Yeon, 2020. "A new test of asset return predictability with an unstable predictor," Economics Letters, Elsevier, vol. 196(C).
    42. Brown Jr., William D. & Fernando, Guy D., 2011. "Whisper forecasts of earnings per share: Is anyone still listening?," Journal of Business Research, Elsevier, vol. 64(5), pages 476-482, May.
    43. Braouezec, Yann, 2009. "Financing constraint, over-investment and market-to-book ratio," Finance Research Letters, Elsevier, vol. 6(1), pages 13-22, March.
    44. Demeter, Krisztina & Matyusz, Zsolt, 2011. "The impact of lean practices on inventory turnover," International Journal of Production Economics, Elsevier, vol. 133(1), pages 154-163, September.
    45. Wan, Xiang & Britto, Rodrigo & Zhou, Zenan, 2020. "In search of the negative relationship between product variety and inventory turnover," International Journal of Production Economics, Elsevier, vol. 222(C).
    46. Fatica, Serena & Gregori, Wildmer Daniel, 2020. "How much profit shifting do European banks do?," Economic Modelling, Elsevier, vol. 90(C), pages 536-551.
    47. Toloo, Mehdi & Keshavarz, Esmaeil & Hatami-Marbini, Adel, 2021. "Selecting data envelopment analysis models: A data-driven application to EU countries," Omega, Elsevier, vol. 101(C).
    48. Toloo, Mehdi & Keshavarz, Esmaeil & Hatami-Marbini, Adel, 2018. "Dual-role factors for imprecise data envelopment analysis," Omega, Elsevier, vol. 77(C), pages 15-31.
    49. HATAMI-MARBINI, Adel & EMROUZNEJAD, Ali & AGRELL, Per J., 2014. "Interval data without sign restrictions in DEA," LIDAM Reprints CORE 2565, Université catholique de Louvain, Center for Operations Research and Econometrics (CORE).
    50. Chung, Kee H. & Lee, Albert J. & Rösch, Dominik, 2020. "Tick size, liquidity for small and large orders, and price informativeness: Evidence from the Tick Size Pilot Program," Journal of Financial Economics, Elsevier, vol. 136(3), pages 879-899.
    51. Wen-Chih Chen & Andrew Johnson, 2010. "The dynamics of performance space of Major League Baseball pitchers 1871–2006," Annals of Operations Research, Springer, vol. 181(1), pages 287-302, December.
    52. Charnes, A. & Cooper, W. W. & Golany, B. & Seiford, L. & Stutz, J., 1985. "Foundations of data envelopment analysis for Pareto-Koopmans efficient empirical production functions," Journal of Econometrics, Elsevier, vol. 30(1-2), pages 91-107.
    53. Ghasemi, Mohammad Reza & Ignatius, Joshua & Rezaee, Babak, 2019. "Improving discriminating power in data envelopment models based on deviation variables framework," European Journal of Operational Research, Elsevier, vol. 278(2), pages 442-447.
    54. Brooks, Chris & Henry, Olan T., 2000. "Linear and non-linear transmission of equity return volatility: evidence from the US, Japan and Australia," Economic Modelling, Elsevier, vol. 17(4), pages 497-513, December.
    55. Jenkins, Larry & Anderson, Murray, 2003. "A multivariate statistical approach to reducing the number of variables in data envelopment analysis," European Journal of Operational Research, Elsevier, vol. 147(1), pages 51-61, May.
    56. Goker, Nazli & Karsak, E.Ertugrul, 2021. "Two-stage common weight DEA-Based approach for performance evaluation with imprecise data," Socio-Economic Planning Sciences, Elsevier, vol. 74(C).
    57. Ardekani, Aref Mahdavi & Distinguin, Isabelle & Tarazi, Amine, 2020. "Do banks change their liquidity ratios based on network characteristics?," European Journal of Operational Research, Elsevier, vol. 285(2), pages 789-803.
    58. Mehdi Toloo & Mona Barat & Atefeh Masoumzadeh, 2015. "Erratum to: Selective measures in data envelopment analysis," Annals of Operations Research, Springer, vol. 235(1), pages 821-821, December.
    59. Tavana, Madjid & Izadikhah, Mohammad & Toloo, Mehdi & Roostaee, Razieh, 2021. "A new non-radial directional distance model for data envelopment analysis problems with negative and flexible measures," Omega, Elsevier, vol. 102(C).
    60. R Farzipoor Saen, 2011. "Media selection in the presence of flexible factors and imprecise data," Journal of the Operational Research Society, Palgrave Macmillan;The OR Society, vol. 62(9), pages 1695-1703, September.
    61. Dyson, R. G. & Allen, R. & Camanho, A. S. & Podinovski, V. V. & Sarrico, C. S. & Shale, E. A., 2001. "Pitfalls and protocols in DEA," European Journal of Operational Research, Elsevier, vol. 132(2), pages 245-259, July.
    62. Lamb, John D. & Tee, Kai-Hong, 2012. "Data envelopment analysis models of investment funds," European Journal of Operational Research, Elsevier, vol. 216(3), pages 687-696.
    63. Charnes, A. & Cooper, W. W. & Seiford, L. & Stutz, J., 1982. "A multiplicative model for efficiency analysis," Socio-Economic Planning Sciences, Elsevier, vol. 16(5), pages 223-224.
    64. Dariush Khezrimotlagh & Wade D. Cook & Joe Zhu, 2021. "Number of performance measures versus number of decision making units in DEA," Annals of Operations Research, Springer, vol. 303(1), pages 529-562, August.
    65. Ramón, Nuria & Ruiz, José L. & Sirvent, Inmaculada, 2020. "Cross-benchmarking for performance evaluation: Looking across best practices of different peer groups using DEA," Omega, Elsevier, vol. 92(C).
    66. Afsharian, Mohsen & Ahn, Heinz & Harms, Sören Guntram, 2021. "A review of DEA approaches applying a common set of weights: The perspective of centralized management," European Journal of Operational Research, Elsevier, vol. 294(1), pages 3-15.
    67. Kaffash, Sepideh & Azizi, Roza & Huang, Ying & Zhu, Joe, 2020. "A survey of data envelopment analysis applications in the insurance industry 1993–2018," European Journal of Operational Research, Elsevier, vol. 284(3), pages 801-813.
    68. Aggelopoulos, Eleftherios & Georgopoulos, Antonios, 2017. "Bank branch efficiency under environmental change: A bootstrap DEA on monthly profit and loss accounting statements of Greek retail branches," European Journal of Operational Research, Elsevier, vol. 261(3), pages 1170-1188.
    69. Angbazo, Lazarus, 1997. "Commercial bank net interest margins, default risk, interest-rate risk, and off-balance sheet banking," Journal of Banking & Finance, Elsevier, vol. 21(1), pages 55-87, January.
    70. Cook, Wade D. & Zhu, Joe, 2007. "Classifying inputs and outputs in data envelopment analysis," European Journal of Operational Research, Elsevier, vol. 180(2), pages 692-699, July.
    71. Basse, Tobias, 2020. "Solvency II and sovereign credit risk: Additional empirical evidence and some thoughts about implications for regulators and lawmakers," International Review of Law and Economics, Elsevier, vol. 64(C).
    72. Ball, Ray & Gerakos, Joseph & Linnainmaa, Juhani T. & Nikolaev, Valeri, 2020. "Earnings, retained earnings, and book-to-market in the cross section of expected returns," Journal of Financial Economics, Elsevier, vol. 135(1), pages 231-254.
    73. William W. Cooper & Lawrence M. Seiford & Kaoru Tone, 2007. "Data Envelopment Analysis," Springer Books, Springer, edition 0, number 978-0-387-45283-8, November.
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