**4.1. Tourism activity and economic growth**

Ever since [11] originally analysed the hypothesis known as tourism-led growth (TLG), i.e., tourism generates economic growth, studies have proliferated which, although agreeing in linking tourism activity and economic growth, present clear differences in the scale of this link. The scale seems to be related to the methodology used, the temporal and territorial framework of study, and the form of measuring the tourism activity in each case [61].

In [61], it was shown that most of the studies are based on the use of time series [62–70], other studies were based on a cross section analysis [49,71–73], and finally some studies used panel techniques, such as those of [12,74–77]. In the afore-mentioned study [61], it was shown that, up to the start of 2013, 87 studies that empirically analysed the relationship between tourism activity and economic growth had been published . Of those, 55 showed the existence of a causality relationship that runs from tourism activity to economic growth, whereby the TLG hypothesis is verified or supported. Of the other published works, 16 identified a two-way relationship between the variables, 9 found a causality relationship between economic growth and tourism activity, and 4 did not find any type of relationship between both variables.

However, the authors state that, even though most of these studies show that there is a link between tourism activity and economic growth, there are clear, simultaneous, differences between the different studies in the magnitude of this link. This magnitude variation seems to be associated with the methodology used, the temporal and territorial framework referred to in each study, and the form of measuring the tourism activity in each case

In a similar direction, the methodological strategies used in the studies that analyse the TLG hypothesis have recently been reviewed, also showing differences in the magnitude of this link based on the methodologies used, as well as on the variable used to measure tourism activity [78]. These conclusions have been ratified by the meta-analysis made in [79]. In that study, important differences are demonstrated referring to the short or long term, the use of additional variables of economic growth in the explanation of the model and the use of different methodologies to measure the tourism activity.

In this regard, the study significantly shows that the value of the effect of tourism on economic growth in the long term, depends on whether the effect of other economic variables on growth is also taken into account, such as physical or human capital, in which case, the effect of tourism activity on growth diminishes remarkably. Thus, these variables should not be excluded from the analysis, if it is required to adequately show in which way tourism activity contributes to economic growth.
