(ProQuest: ... denotes formulae omitted.)IntroductionDuring the last years the tourism industry has witnessed an extraordinary growth which has been accompanied by a substantial increase in environmental costs and other detrimental externalities which are associated with a high influx of tourists. The literature has been able to develop different techniques to evaluate and appraise the positive economic impacts associated with tourism (Tourism Satellite Accounts and General Equilibrium Models, mainly), however, the methodological deficits when appraising the negative impacts persist. It has been recognized that in order to assess and improve sustainable development, analyses of a sector's performance should not only address its economic contributions but also environmental and social dimensions (Gray and Bebbington 1993; Brida et al. 2008; Martin 2009). In response to this recognition, additional methods for auditing performance have evolved, including lifecycle assessment (Hernandez and Leon 2007; Becken and Simmons 2008) and ecological footprinting (Gossling, Borgstrom Hansson, Horstmeierc and Saggeld 2002; Patterson Niccolucci and Bastianoni 2007).Although researchers agree that the environmental impacts of tourism are substantial (Gossling, 2002), the literature has only recently begun to analyze the direct environmental effects of tourist activities. For instance, tourism is responsible for a large proportion of national energy consumption from activities associated with transportation and services rendered at the destination (Becken, 2002; Becken and Simmons, 2002, Becken et al, 2001, 2003; Gossling, 2000; Gossling et al, 2002; Tabatchnaia-Tamirisa et al, 1997). For this reason, it is important to highlight the main economic sectors that are associated with tourism including transportation and/or accommodation. This perspective can be better understood by the nonexistence of a touristic sector in the traditional economic classifications on National Accounts. However, it should be noted that in applying tourism policies, public administration officials should attribute the environmental and social costs of tourism to the industry as a whole and not only to the most representative economic sectors.In order to deal with this problem the United Nations have developed the tourism satellite account (TSA) which helped to measure the true size of the tourism industry and to show that tourism constitutes a significant part of the overall economy instead of just being a minor economic player. The TSA's rely on extracting tourism-related economic activities from existing systems of economic accounts, and generally cover only the direct effects of tourism expenditure in tourism-related industries. Another alternative approach to measure the economic impact of tourism, which may be labelled "visitor survey method", relies on a more direct estimation of tourism volumes and expenditure via formal visitor surveys. Survey methods often use regional economic tools, such as input-output models and multipliers to convert tourist expenditure into the associated income and jobs and to estimate secondary impacts (multiplier effects). However, although these approaches might be valid when economic impact is evaluated, they fail when other kind of impacts have to be measured.Based on the definition of tourism and in order to consider it as an aggregate, a researcher may opt for tourist arrivals as an indicator of pressure and different impacts. Nevertheless, this approach, often available through monthly data, presents two main drawbacks. Firstly, for the tourist imputation to a certain month, the presence of a time lag between the arrival date and the day when a tourist is effectively impacting could result in a bias, and particularly when including tourists arriving at the end of the month. Secondly, and due to tourism patterns which may change over the years or during the same year, the length of stay could be affected and, hence, its omission in the analysis could largely affect the estimated results. …