In previous papers the authors have argued that aid is likely to mitigate the negative effects of external shocks on economic growth (i.e. that aid is more effective in countries which are more vulnerable to external shocks). Recently an important debate has emerged about the possible negative effects of aid volatility itself. However, the cushioning effect of aid may involve some volatility in aid flows, which then is not necessarily negative for growth. In this paper the authors examine to what extent the time profile of aid disbursements may contribute to an increase or a decrease of aid effectiveness. They first show that aid, even if volatile, is not clearly as pro-cyclical as is often argued, and, even if pro-cyclical, is not necessar...