“…Moreover, the large scale of operations leads to a higher number of lines connecting ports and, thus, increasing the competitive pressure in the transport market and, as a result, lowering the cost of transport services. 9 These models have been applied to trade Metcalf, 2005, 2006;Papazoglou et al, 2006;Armstrong 2007;Spies and Marques, 2009;Marques, 2011), migration (Gil-Pareja et al 2006;Marques, 2010), FDI (Head and Ries 2008), and tourism (Eilat and Einav, 2004;Gil-Pareja et al, 2007;Santana et al, 2010;Fourie and Santana 2013;Rosselló and Santana-Gallego 2014). Moreover, this specification has also been used both in the international and regional context (see, for the case of Spain, Sansó et al, 1990, Sanz, 2000and Gil-Pareja et al, 2005 variable cost, which depends on distance, and a specific trade cost, which exists only for some trade partners (in our case, islands).…”