Disasters, 2003, 27(1): 72–90 © Overseas Development Institute, 2003. Published by Blackwell Publishing, 9600 Garsington Road, Oxford OX4 2DQ, UK and 350 Main Street, Malden, MA 02148, USA. Humanitarian Information Systems and Emer- gencies in the Greater Horn of Africa: Logical Components and Logical Linkages Daniel Maxwell Ben Watkins CARE International World Food Programme Natural and man-made emergencies are regular occurrences in the Greater Horn of Africa region. The underlying impoverishment of whole populations is increasing, making it more difficult to distinguish between humanitarian crises triggered by shocks and those resulting from chronic poverty. Shocks and hazards can no longer be seen as one-off events that trigger a one-time response. In countries that are both poor and exposed to frequent episodes of debilitating drought or chronic conflict, information needs tend to be different from the straightforward early warning/commodity accounting models of information systems that have proven reliable in past emergencies. This paper describes the interdependent components of a humanitarian information system appropriate for this kind of complex environment, noting the analytical links between the components and operational links to programme and policy. By examining a series of case studies from the Greater Horn region, the paper demonstrates that systems lacking one or more of these components will fail to provide adequate information — and thus incur humanitarian costs. While information always comes with a cost, the price of poor information — or none — is higher. And in situations of chronic vulnerability, in which development interventions are likely to be interspersed with both safety nets and emergency interventions on a recurrent basis, investment in improved information is a good investment from both a humanitarian and a financial viewpoint. Keywords: humanitarian information systems, chronic vulnerability, early warning, needs assessment, monitoring and evaluation, Greater Horn of Africa. Introduction Emergencies of both natural and man-made causes are increasing in frequency and complexity in the Greater Horn of Africa region. Often treated in the past both conceptually and programmatically as one-off events caused by natural phenomena, shocks are recurrent, and emergencies are caused by numerous factors, many of which are chronic. Emergencies are defined in terms of a variety of categories of information and in turn, emergency preparedness and response are driven by information. But often the kind of information sought may simply not be available or the available information is poor in quality, methodologically ad hoc, spotty in coverage and interpreted out of context by external analysts. As emergencies increase in frequency and severity, as the line between acute crises and chronic vulnerability blurs and as needs for mitigation, response and dealing with chronic poverty grow, information needs tend to proliferate more rapidly (UNHCR/WFP, 2000; Buchanan-Smith, 1996; Keen and Ryle, 1996).