**3. Empirical advances of tourism competitiveness: international indicators**

Those theoretical or conceptual models of tourism competitiveness have also brought about a very considerable empirical advance [5–9,20,24–28]. The models proposed in those works have emphasised the need to define tourism competitiveness by means of a set of interrelated variables, which necessarily have to be measurable to be able to assess that competitiveness. This has led to interest in a large variety of indicators that are being proposed in the economics literature. These indicators are those that make reference to inputs and other results, or outputs and other instruments [6], those that are directly linked to competitiveness with other tourism areas, and those that are related to more general elements that can affect this competition. There are authors who offer a list of indicators of competitiveness of tourism destinations [26, 29].

The case study of [29] lists more than 150 indicators of competitiveness of tourism destinations, grouped into different categories (inherent resources, 11; created resources, 21; complementary factors and resources, 28; management of the destination, 34; local conditions, 25; conditions of the demand, 4; and other indicators of a macroeconomic nature and of socioeconomic prosperity, 32). Also, the study of [26] lists a lower number of indicators (68), although it is sometimes difficult to find the value of those indicators in all the analysed destinations.

Along this line, some institutions have echoed the need to provide data for the construction of tourism competitiveness indicators, and it is possible, above all, to highlight the World Travel and Tourism Council (WTTC) and the World Economic Forum (WEF).
