Traditionally, donor programmes have been established using a simple formula, whereby SPs estimate the total overhead for a programme through tender, against a fixed set of inputs and workplan. In these programmes, clients need to wait months or years before assistance is deployed due to procurement procedures, by which time resource allocation, costs, and plans are inevitably incorrect due to changes in the context. By contrast, facility models have proved to be an economic and effective way for donors to deliver a complex and innovative infrastructure programme.