The requirements of project management vary widely according to the nature of the project and the number of objectives and agencies involved. In particular, management techniques appropriate for physical projects (building and maintaining infrastructure, operating industrial plants and utilities) differ significantly from those needed in people-centred development (small farmer agriculture, education, family planning, health and nutrition; and infrastructure and housing projects where beneficiaries participate in design, construction, or maintenance). In general, methods in physical projects are well understood: constructing and operating an oil refinery may not be simple, but the technology is well specified and can be applied in different countries and cultures. The main managerial requirements are to train and motivate staff and to strengthen operational control. Because performance can be measured in terms of physical output' there is much scope for reinforcing government efforts by using private contractors.
In contrast, less is known about how to change patterns of behaviour so that people adopt new farming methods or birth control, because cultural influences predominate. These uncertainties about people-centred development are combined with less managerial control, since success depends on stimulating peoples' voluntary participation. Management therefore requires experimentation, flexibility, and a willingness to work closely with programme beneficiaries to learn about, and respond to, local needs. Governments often find programmes involving the poorest are the most difficult to make effective.
A distinction can be usefully made between the management approaches needed in physical and in people-centred development. Complications tend to ensure when projects and programmes involve several implementing agencies. Again, there is a contrast between physical projects, which can rely on contracts between agencies, and people-centred programmes, which need continuous informal contacts among field staff.