The coherence and effectiveness of engagement with the world's 'fragile and conflictaffected states' - beyond ethical imperatives and geo-strategic considerations - turns on answers to two vexing questions. First, on what defensible basis is any given country, at any given historical moment,...

Rising standards for accurately inferring the impact of development projects has not been matched by equivalently rigorous procedures for guiding decisions about whether and how similar results might be expected elsewhere. These 'external validity' concerns are especially pressing for 'complex'...