Due to their multidimensionality and complexity, indicators are often used to measure and track progress towards travel and tourism sustainability at a destination/country level. These sustainability indicators are often forms of composite indices and can be used to drive change at national and institutional level. Conceptually, “composite indicators are based on sub-indicators that have no common meaningful unit of measurement and there is no obvious way of weighting these sub-indicators”, and technically, they are “mathematical combinations of a set of indicators” (Saisana, 2004, p. 1). Although they are not fully inclusive (see for example issues emerging with respect to university rankings, which use composite indices), the society accepts the use of indices for a variety of purposes including public debate, complex decision making, strategic marketing, benchmarking and to evaluate/drive performance based on Specific, Measurable, Achievable/Agreed, Relevant/Realistic, and Timebound (SMART) objectives (OECD, 2015).