So therefore it all depends what your criteria are for "the world's poorest country" ..? Some UN surveys / statistical reports will use average or maximum income per head of population as the line of judgement, while other (predominantly economic) bodies may use the gross domestic product of the state as the deciding factor, and others again may use simply the overall number of people estimated to be living below the government-determined "poverty line" for that country. And there are various other minor criteria too, used for different reasons by different organisations, so you need to define your terms a little more closely to get any meaningful answer to your question.