“…Empirical micro‐level investigations have also been conducted widely (Wagner, , ; Thomas and Narayanan, 2012). A few published studies have focused on the joint effect of fixed export costs and productivity on firm‐level export behaviour (Jorgensen and Schroder, , Castro et al , ) and the influence of country efficiency on firm performance (Montagna, ; Falvey et al , ). A sorting mechanism based on variable and fixed costs associated with exports can be used to explain the self‐selection effect on international trade.…”