Acknowledgments

The authors gratefully acknowledge financial support by the United States Agency for International Development (USAID), Africa Bureau, Office of Analysis, Research, and Technical Support, Division of Food, Agriculture, and Resources Analysis, Basic Ordering Agreement, DAN-4111-B-00-9112-00, and most particularly the enthusiastic encouragement of George Gardner, Shirley Pryor, and John van Dusen Lewis of USAID.

The project could not have been attempted without the prior existence of detailed household-level data sets collected by the International Food Policy Research Institute (IFPRI) in collaboration with various African and Consultative Group on International Agricultural Research (CGIAR) partner institutions. The close involvement in the present project of members of the original country research teams that collected the data was also essential, both to ensure that the data were interpreted correctly and to add location-specific knowledge to the analysis.

The research team also acknowledges with gratitude its debt over many years to other colleagues who were involved with the projects that originally collected the data and helped shape the views of the present authors. In particular, Thomas Reardon, currently of Michigan State University (MSU), had a key role in shaping much of IFPRI's work in the Sahel in the 1980s, most particularly on income diversification and household expenditure issues.

The Burkina Faso data set was collected in 1984/85 in collaboration with the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT). Peter Mat-Ion, then ICRISAT's lead economist for West Africa, and Thomas Reardon, then of IFPRI, assisted by Christopher Delgado, played lead roles in designing the survey and collecting the household expenditure data used in Chapter 4.

The Niger data set was collected in 1989/90 in collaboration with the Institut National de la Recherche Agronomique du Niger (INRAN) and the ICRISAT Sahelian Center. Samba Ly of INRAN, Thomas Reardon, and Jojo Baidu-Forson of ICRISAT collaborated with Jane Hopkins on the collection of the Niger data used in Chapter 5.

The Senegal data set was collected in 1989/90 in collaboration with the Institut Sgalais de Recherches Agricoles (ISRA). Thomas Reardon, and Bocar Diagana and Abdoulaye Fall of ISRA collaborated with Valerie Kelly in the collection of the Senegal data used in Chapter 6. Special acknowledgment is also made of the assistance of Aliou Diagne, then of MSU and now of IFPRI, in improving the analysis of the Senegal expenditure data.

The Zambia data set was collected in 1985/86 in collaboration with the Rural Development Studies Bureau of the University of Zambia. John Milimo, then of the Rural Development Studies Bureau, Raphael Celis, then of IFPRI, and Sudhir Wanmali and Neal Bliven of IFPRI collected the Zambian data used in Chapter 7, with survey design input from Peter Hazell.

The Zimbabwe data were collected in 1987/88 in collaboration with the Department of Physical Planning, Ministry of Local Government, Rural and Urban Development, Government of Zimbabwe. Sudhir Wanmali of IFPRI and Jonathan Zamchiya of the Department of Physical Planning, Zimbabwe, collected the Zimbabwe data used in Chapter 7.

The authors would also like to acknowledge the helpful written comments received on previous drafts from Keijiro Otsuka and Dean DeRosa. They are also very grateful for the copious, detailed, and insightful comments received from Alain de Janvry. Remaining deficiencies of the report are the responsibility of the authors.

Within this team-authored document, primary responsibility was taken as follows: Christopher Delgado drafted the summary; Delgado, Jane Hopkins, Valerie Kelly, and Claude Courbois drafted the introduction; Delgado and Anna McKenna drafted the survey of the literature; Delgado and Jayashree Sil drafted the conceptual framework, the model (based on previous work by Peter Hazell), and the Burkina Faso chapters; Hopkins, Delgado, and Peter Gruhn drafted the Niger chapter; Kelly, Delgado, and McKenna drafted the Senegal chapter; Hazell and Behjat Hojjati drafted the Zambia and Zimbabwe chapter; and Delgado, Hopkins, and Kelly drafted the conclusion. Overall editing and revision in response to reviewers' comments were carried out by Delgado and Courbois.