The index, published annually by the Mo Ibrahim Foundation, measures governance in Africa’s 54 nations across four areas: safety and the rule of law; participation and human rights; sustainable economic opportunity; and human development.

While there had been considerable improvements in governance across Africa over the past 15 years, progress had been much more marginal since 2011.

Two of the four measures show a decline: safety and the rule of law and sustainable economic opportunity.

This latter category, is underpinned by assessments of infrastructure investment, business environment and public management. While infrastructure investment had picked up, there had been declines in public management, the rural sector and particularly the business environment.

On safety and rule of law, progress was being impeded by cross-border conflicts.

The index showed that, once again the continent’s top performers remained largely unchanged. Mauritius occupied the top spot, with an overall governance score of 79.9 out of 100. It was followed by Cabo Verde (74.5), Botswana (74.2) and South Africa (73.0). Namibia (70.4) moved up to claim the fifth spot in the index from Seychelles (70.3), which was pushed into sixth place.

At the bottom of the index was Somalia with a governance score of just 8.5, although this was an improvement on last year’s score. Other weak performers were South Sudan (19.9), Central African Republic (24.9), Sudan (28.3) and Eritrea (29.9).

A regional analysis of the index shows that Africa’s strongest performing nations tend to be located in southern Africa, while the weakest were in the central African region.

The most strongly improved countries in governance terms were Côte d'Ivoire, Zimbabwe and Senegal.

Launching the index at a debate in London yesterday, Ibrahim stressed the importance of governance, saying policy decisions needed to be based on facts and data. “Governance is measurable, not mysterious. The ordinary man or woman in the street needs to be able to talk about governance.”

But he also emphasised the diversity of the African continent and the many different things that were happening and cautioned against drawing too many generalisations from the data.

Donald Kaberuka, former president of the African Development Bank, told the debate that stronger performers had more diverse economies and were not so reliant on commodities.

Former Botswana president Festus Mogae also participated in the debate. Asked why southern African nations tended to have stronger governance, he suggested that it could be that the region had greater democracy than other parts of Africa.

The Ibrahim Index of African governance can be viewed here.

Top 5

1.    Mauritius

2.    Cabo Verde

3.    Botswana

4.    South Africa

5.    Namibia

Bottom 5

50. Eritrea

51. Sudan

52. Central African Republic

53. South Sudan

54. Somalia

African average: 50.1 (improvement since 2011 +0.2)