Abstract

Abstract
This paper presents a literature review on Data Envelopment Analysis assessments of economic efficiency, covering methodological developments and empirical applications. We review the seminal models for economic efficiency measurement, involving the optimization of cost, revenue, and profit. The applications of the different modelling approaches are also discussed. Based on a content analysis of papers published between 1978 and 2020 in various sectors, the main areas of study are identified, and the pathways of research developments are discussed. Most studies are based on disaggregated quantity and price data. In addition, the use of panel data is prevalent compared to cross-sectional studies. There is a preponderance of input -oriented studies focused on cost efficiency rather than revenue or profit efficiency. Informed by the historical evolution of economic efficiency assessments portrayed in this review, we suggest directions for future developments. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

Abstract
A significant challenge in asset management is the selection of investment projects for infrastructures, which often relies on subjective judgement and lacks structured decision support methods. This challenge is particularly complex in water systems due to the diverse and heterogeneous nature of the components requiring investment. While the infrastructure value index (IVI) is widely used to characterise assets and support investment decisions in the water sector, its application in optimisation models for generating efficient project portfolios remains unexplored. To address this research gap, this study introduces optimisation models for generating investment portfolio plans in water systems' asset management. The proposed approach includes two mixed-integer linear programming (MILP) models that determine optimal solutions and an evolutionary algorithm that offers sub-optimal alternative investment selection plans to provide decision-makers with additional choices for balancing optimal outcomes. The primary contribution of this research is the combined utilisation of MILP and evolutionary algorithms, integrating the IVI into the decision-making process. These tools provide decision-makers with structured methods for defining investment plans and minimising the subjective elements typically associated with such processes. To illustrate the effectiveness of the models, a case study is presented involving a pumping station of a Portuguese water company. The results demonstrate the practical application and benefits of the proposed approach in optimising investment decisions. This research contributes to advancing asset management practices by integrating quantitative optimisation techniques and leveraging the IVI, thereby enhancing the objectivity and efficiency of investment planning in water systems' asset management.

Abstract
The Single Supervisory Mechanism (SSM) was implemented as a first step towards a Banking Union in November 2014. This paper investigates the impact of the SSM on Eurozone banks' efficiency and position of best-practice frontier. It is based on a balanced panel analysis of 931 European bank-year observations from 2011 to 2017 (133 banks, seven years). The study uses Data Envelopment Analysis and a difference-in-differences approach to explore the evolution of banking performance. We found that the SSM had a negative impact on the efficiency levels of Eurozone banks, particularly in the year after the introduction of the mechanism. Additionally, we observed that the frontier formed by non-Eurozone European Union banks is more productive than the frontier of Eurozone banks in all the years analysed. Both efficiency and frontier position show evidence of a recovery trend in more recent years for both groups. We also found that while Equity-to-Asset Ratio, Return on Average Assets and Gross Domestic Product per capita positively impacted banks' efficiency, domestic credit provided by banks expressed as %GDP had a negative impact on efficiency.

Abstract
There are still important theoretical and empirical gaps in understanding the role of best practices (BPs), such as quality management, lean and new product development, in generating firm's performance advantage and overcoming trade-offs across distinct performance dimensions. We examine these issues through the perspective of performance frontiers, integrating in novel ways the resource-based theory with the emergent practice-based view. Hypotheses on relationships between BPs, performance advantage, and trade-offs are developed and tested with stationary and longitudinal (recall) data from a global survey of manufacturing firms. We use data envelopment analysis, which overcomes limitations of mainstream methods based on central tendency. Our findings support the view that BPs may serve as a source of enduring competitive advantage, based on their ability to lead to a heterogeneous range of dominant and difficult-to-imitate competitive positions. The study provides new insights on contemporary debates about the role of BPs in generating performance advantage and how practitioners can sustain internal support and extract benefits from them.

Abstract
This work delves into the crucial role of service quality in the water supply and sanitation sectur. Despite extensive research and implementation of quality management practices in this sector, a universally accepted definition of quality is still lacking, resulting in varikoza service quality assesunent procedures that are difficult to compam. To address this issue, the World Bank launched the Thility of the Future' (UoF) programme, aiming guide water service providers in their efforts to become future-focused utilities that offer reliable, safe, Inclusive, transparent, and resposesive services through best-fit practices. Building upon the Damework provided by the lof programme, this study proposes the Water Utility Service Quallity Index (WUSOI) composite Indicator that reflects the quality of service provided by water supply and sanitation utilities from a customer perspective. Based on Data Envelopment Analysis, the Benelli-of-the-Douht appenach is employed to assign weights for aggregating the indicators representing the diverse performance dimensions. The study operationalines the WUSOI to assess the quality of Purtuguese wholesale water and wastewater companies using data enflected by the national regulator of water and waste services. A Multiple Criteria Decision Analysis technique, the Deck of Cands method, is used to specify an indicator of transparency from the information made available by the regulated utilities. The results show the effectiveness of this tool for evaluating and measuring service quality at the company level. Additionally, the findings highlight areas for Improvement in the utilities' performance. By enabling companies and regulators to identify areas for improvement, the WUSOI can support the delivery of high-quality services to customers.