The leading and intermediate indicators will be useful if they trigger early interventions aimed at ensuring adequate food supplies for the population and at maintaining the purchasing power of vulnerable groups. These measures have included temporary government subsidies for food crops, "food-for-work" programs; government-run, fixed-price food shops; rural employment schemes; the distribution of drought-resistant seeds; and the release of food reserves.
Effective early warning systems might help avert major population movements, thereby allowing local government and international and private voluntary organizations (PVOs) to provide assistance in situ without major disruption in traditional social structures and lifestyle patterns. Affected communities can be surveyed, needy households identified, food and other relief supplies distributed, and major epidemics averted with greater ease and effectiveness in a stable population than in a temporary refugee settlement. National early warning systems have proved effective in preventing famine during the past decade in India and Botswana (8). When populations are forced to migrate en masse, they usually end up in camps or urban slums characterized by overcrowding, poor sanitation, substandard housing, and limited access to health services. These conditions hamper the effective and equitable distribution of relief supplies and promote the transmission of communicable diseases.