I’ve never been convinced by extant treatments of this topic. Here is one further stab at the problem, from Afrobarometer (pdf):
New data from Round 5 of the Afrobarometer, collected across an unprecedented 34 African countries between October 2011 and June 2013, demonstrates that lived poverty remains pervasive across the continent. This data, based on the views and experiences of ordinary citizens, counters projections of declining poverty rates that have been derived from official GDP growth rates. For the 16 countries where these questions have been asked over the past decade, we find little evidence for systematic reduction of lived poverty despite average GDP growth rates of 4.8% per year over the same period. While we do see reductions in five countries (Cape Verde, Ghana, Malawi, Zambia and Zimbabwe), we also find increases in lived poverty in five other (Botswana, Mali, Senegal, South Africa and Tanzania). Overall, then, despite high reported growth rates, lived poverty at the grassroots remains little changed. This suggests either that growth is occurring, but that its effects are not trickling down to the poorest citizens in fact, income inequality may be worsening), or alternatively, that actual growth rates may not match up to those being reported. The evidence also suggests, however,that investment in infrastructure and social services are strongly linked with lower levels of lived poverty.
I am not suggesting that these are “the right” numbers, and you might object that they are based on individual responses to questions. Still, the numbers do show a very definite poverty reduction in the case of Ghana and some other countries with good news, so the responses do not seem entirely unconnected to reality. In any case I have long been suspicious about how much African growth has been resource-generated rather than based in ongoing gains in agricultural productivity.
If you would like better news from Africa, here are some figures from last year about declining child mortality. Here are some new results comparing Africa to earlier stages in British history, the original paper is here (pdf).