How to measure tourism sustainability? Proposal of a tourism sustainability index for Portugal

The purpose of this paper is to analyse the evolution of sustainability indicators, present in the various national tourism plans in Portugal, and, subsequently, to propose the creation of a tourism sustainability index that can provide a perspective on the level of sustainable development. To achieve this, a qualitative methodology was used, which consisted of document analysis of the main national tourism plans identifying the indicators used to measure sustainability over time and identifying the different possible methodologies for the implementation of a tourism sustainability index. As a result, it was possible to determine the methodology that seems more suited to implement a tourism sustainability index for Portugal, taking in consideration the different indicators analysed and made available by the Portuguese Tourism Board. As for limitations, this paper only proposes a methodology for the calculation of the sustainability index but does not calculate the index itself. This is subject of future work, which will also make it possible to verify the quality of the index itself and to adjust the methodology, if needed. The implementation of this methodology may be an important contribution to facilitate a practical analysis and comparison of sustainable development among different cities, regions or even countries. Although there have been authors that have proposed sustainability indices for other areas of activity, there has never been a tourism sustainability index proposal for Portugal.