D Data envelopment analysis, tourism Se ´rgio P. Santos and Carla A. F. Amado Faculty of Economics, University of Algarve, Faro, Portugal Data envelopment analysis is a nonparametric technique for measuring the relative efficiency of multi-input and multi-output production units, usually called decisionmaking units. The efficiency measure originally proposed maxi- mizes the ratio of the weighted sum of outputs over the weighted sum of inputs, subject to the condition that the efficiency of each unit is smaller than or equal to 1. In order to identify the efficient decisionmaking units, the data envel- opment analysis technique constructs a best prac- tice frontier, to which each inefficient unit is compared, allowing for the identification of suit- able learning peers as well as targets for perfor- mance improvement. Notably, Cooper et al. (2007) present a comprehensive review of this technique. Since its advent in 1978 (Charnes et al. 1978), there has been an impressive growth in the field, both in terms of methodological developments and practical applications. On the methodologi- cal side, some of the topics that have attracted most attention include the development of vari- ous models for measuring efficiency, approaches for incorporating restrictions on multipliers, models for examining the status of variables, and models for evaluating data variations (Cook and Seiford 2009). On the practical side, the technique has been extensively applied in indus- tries such as banking, healthcare, agriculture, ▶ transportation, ▶ education, and tourism (Liu et al. 2013). Banker and Morey (1986) were the first to apply the technique to the tourism and hospitality industry, specifically to the restaurant sector. Since then, this technique has attracted consider- able ▶ attention from tourism researchers and has also been used to analyze the efficiency of hotels, travel agencies, tourism offices, tour operators, and even destinations. Issues studied through this approach include measuring different types of efficiency, ranking decisionmaking units, identi- fying sources of inefficiency, exploring produc- tivity changes over time, evaluating the impact of different management styles and ownership on performance, evaluating the effectiveness of pro- grams and policies, and managing destinations. Although its successful application can face challenges, the research carried out in the last three decades shows that this technique has strong potential to contribute to performance improvement not only in tourism but also in many other industries. For its potential to be fully utilized, it is important, however, to move away from the “black box” type of evaluation and implement formative evaluation exercises aimed at developing a deep understanding of the struc- tures and processes associated with best practice. # Springer International Publishing Switzerland 2015 J. Jafari, H. Xiao (eds.), Encyclopedia of Tourism, DOI 10.1007/978-3-319-01669-6_47-1