The report by consultants Valid International on the DEC 2002/2003 Southern Africa appeal, which raised £16m, says that the relief effort saved lives and alleviated suffering, but it noted: "One would expect those communities that had developed their capacity with the assistance of DEC agencies would be better able to weather the shock, when compared with adjoining communities in a similar state of poverty. They were not.
"The evaluation team did not find a single example where an agency could clearly demonstrate that its development programme clients were better placed to cope with the food crisis than communities not in receipt of long-term aid."
Jane Moyo, spokeswoman for the DEC, said the report demonstrated that aid agencies had to broaden their approach.
"This just illustrates the depth of the crisis. Many agencies have been working there for years but this was a new type of crisis about HIV and Aids as well as food. Aid agencies, and governments in the region, are struggling to cope.
"Unless you tackle poverty not just at the field level, but at the national and international level as well, and address the broader causes of poverty, then agencies will find it difficult to make any difference at all," Moyo added.
The report also criticises agencies for misrepresenting the scale of the crisis. "The crisis was overstated in terms of the threat of famine, but at the same time the chronic roots of the crisis were understated," it says.
World Vision, for example, warned of a "crisis of biblical proportions".
Concern said that only large-scale delivery of food could prevent "catastrophe on the scale of the 1984 Ethiopian famine".
The report warns that the agencies risk the success of future DEC appeals by such exaggeration. It recommends training for marketing staff in the DEC's code of conduct.