Under China's prereform foreign trade system, exports were determined by the level of planned surpluses and imports by the level of planned shortages. It was important that foreign trade was fully integrated into the national economic plan. A deficiency in raw material imports, for instance, would hamper domestic production and create a ripple of coordination problems. In contrast, under the postreform system, exports and imports are no longer determined by an elaborate coordination process. Specialized ministries, local governments, and enterprises, now sharing with the central government the power to engage in foreign trade, are to a certain extent allowed to make their own foreign trade decisions. Foreign trade is not, and does not have to be, rigidly planned, because enterprises and local governments are now faced with relatively flexible supplies of material inputs from domestic and foreign sources. The central government only has to draw up a rough foreign trade plan and deal with major exports and imports. Under this new economic system, foreign trade is much less destabilizing than it was under the prereform system, given that foreign trade is no longer strictly associated with massive and forced reallocation of resources from one sector to the other. The 1981–2 foreign trade slump and the 1984–6 foreign trade boom had relatively little impact on China in terms of national output.