This paper gives a conceptual overview of the openness and vulnerability, sharing which in both cases respectively depends on economic policy and on structural factors, independent from policy. It focuses on openness policy, proposed to be measured by the residual of an openness function estimated only from structural factors, and on structural vulnerability, proposed to be measured from indicators reflecting the size of the shocks and the exposure to them. Some joint effects of an openness policy and of structural vulnerability are then presented, relying on several previous cross-section regressions and summarized on six proposals : 1/ whereas economic growth is raised by export growth, it is lowered by export instability, 2/ vulnerability (instability) affects more total factor productivity than capital accumulation, 3/ structural vulnerability to a large extent operates through economic policy intermediary variables, 4/ negative effects of export instability are dampened by an open policy, 5/ they are also dampened by foreign aid, 6/ an appropriate measurement of macroeconomic performance both reflecting the quality (openness) of the policy and taking into account structural vulnerability, can be used as a criterion for aid allocation.
