Development and efficiency

In the same class, one of the students (Tim) mentioned that efficiency is essential to development. This simple claim, which I think is correct, is easy to overlook if you are critiquing capitalist conceptions of development. But the fact of the matter is that if you want to improve people's material wellbeing, you have to improve the efficiency of their work. (Or perhaps you can just help them build better sewerage systems or houses?) Similarly to reduce material throughput in production and consumption, you have to improve efficiency. The consequent questions then are how much efficiency do we need? how quickly do we need to achieve it? and what forms of social organization will let us achieve the desired level of efficiency in the desired time?