Chapter 3 and this expense can only be justified if the collection of information informs action and policy. Monitoring cannot be an academic exercise. It should result in improvements in programme design and delivery and more appropriate policy implementation. The issue oft the linkage between the monitoring system and the relevant decision making body is as important as the structure and content of the monitoring system itself. Monitoring systems can be loosely classified into two types. National and Global monitoring systems have strengths in reporting on food availability at national and regional levels, but tend to be weak in reporting on household physical and economic access to the food available. Local and household based monitoring systems tend to be much stronger on monitoring access, but are often poorer at building up a picture of overall food availability. Information may be explicitly collected for the monitoring system, but it is frequently possible to use information which is already collected as part of the country's statistical programme, or as a by-product of existing programmes. When existing data collection systems can be utilised as part of a monitoring system this can cut down costs considerably. Cost effectiveness should be a major criteria in the development of a monitoring system. Money spent on collecting and analysing data could otherwise be spent on programme implementation. This should be kept in mind when the expansion of data collection is being considered. Timeliness is another important element to be considered when developing a monitoring system. This is most obvious when examining an early warning system, where the major purpose is to warn of upcoming food crises. This may be of limited use if it takes three months to analyse the information and report to government. It is also an important factor in other types of monitoring system, whether at the household level or for programme assessment. 5.2 National and global monitoring systems The most common form of national food security monitoring system is the early warning system. These were instituted in many countries in the period immediately after the 1974 World Food Conference. They are based on the assumption that the scale of food crises could be monitored at the macro level in an economy and that the major issue is one of food availability. Early warning systems often tend to be donor oriented, and one of their major purposes is to alert the donor community to food crises which may require emergency concessional imports. To assess likely food supply, a number of indicators are collected. In most countries, estimates are made of agricultural production in the months leading up to the harvest period. These are supplemented by, and in part may be based on meteorological information. Rainfall may be collected from weather stations and allow for the determination of the probability of rainfall failure. Rainfall monitoring has been enhanced in many countries by satellite remote sensing for monitoring cold cloud formation. In the past few years in southern Africa, satellite sensing has also allowed assessment of vegetative growth, particularly important in assessing grazing in livestock economies. All this improves the estimates of domestic food production. - 99 -