This paper considers the effects of a more or less trade and capital openness on the instability of the growth rate. Indicators of outward looking policies are estimated by eliminating the impact of structural factors through a panel standardization equation. Then indicators of growth instability are estimated. Open trade policies are assumed to be stabilizing because they improve the working of markets. But open financial policies, when the financial system is underdeveloped, may increase instability due to speculative capital flows. Econometric analysis relying on a large sample of developed and developing countries for three periods beginning in 1970 allows to not reject these assumptions.