It was argued in Chapter 3 that the demand for imports was initially determined by the creation of material balances which highlighted the major items in deficit supply in the economy, which planners attempted to fill with imports. In this section I shall argue that the deficits between domestic supply and demand resulted from a combination of the policy of extensive growth (which increased the demand for investment goods, labour and raw materials at a rate that did not automatically correspond to the potential growth of supply from domestic sources) and the planning system which provided producers and consumers with little or no incentive to either increase production or reduce consumption of items for which domestic demand was growing faster than supply.