Briefly, there are two main approaches to delivering assistance. One that comes from the outside and tells people what they need and what they should do, think FMI or World Bank or some (many?) NGOs. The other that comes from the people, who say “This is what we want and this is the help we need”.
What should be the approach chosen by a volunteers-run organisation? Is there a middle way? This is an important point to discuss and here is an example to illustrate the dilemna.
A small community in Africa believes that a good education helps the youths to find better jobs and therefore earn a better living which will benefit the whole community. They decide to built a school and request help from the organisation.
In the “It’s the community who lead” model, the volunteer will support the community in their goal of building a school. After all, that's what they want.
In the “FMI” model it is the organization that tells the community what to do, that needs, assets and community skills need to be assessed first and that only then the decision will be taken to built or not a school.
Who knows better? I think it is irrelevant. What is relevant is the situation. For instance, there may be a school in a nearby village that can take the children on board. This school may be 10-20 km away from the community, but it is possible that developing a bus service between the two communities will be more profitable for both communities. The organizations and teh community should be open minded to different solutions.
My point here is that there shouldn't be any narrow-minded position and that the dogma “the Community/Organization knows better is irrelevant”. The consequence of this approach is that mechanisms are needed to evaluate options and to decide in collaboration with the community which solution is better.