The Ibrahim Index of African Governence weighs how effective a government is by several factors. Some of the factors include saftey, human rights, economic opportunity and development. The Ibrahim Foundation does not use poverty and health statistics in the index as they say the statistics are not comprehensive.
The top five performing governments according to the Ibrahim Index are Mauritius, Seychelles, Botswana, Cape Verde and South Africa. The lowest ranking governments on the index are Somalia, Chad, Republic of Congo, Zimbabwe and Eritrea. You can go the foundation website to see the complete overview of the rankings.
From the Guardian, Mo Ibrahim has this commentary on the index.
The index is a comprehensive assessment of governance quality in Africa, across 88 criteria grouped into four main categories: safety and rule of law; participation and human rights; sustainable economic opportunity; and human development. These four together constitute the cornerstone of a government's obligations to its citizens.
As one would expect, results vary significantly across countries. However, there are important global trends that are cause for hope as well as concern. For a majority of countries, progress in economic and human development is significant. Improvements in these categories have been recorded in over 40 out of 53 African states. On economic management, on the provision of health, on welfare, improved governance is making a substantial impact on quality of life for hundreds of millions of people. Not only has there been overall progress in each of these important areas but, importantly, no country across the whole continent has seen its performance decline significantly.
These are more than just numbers. I have seen first hand how critical these improvements are to Africans' daily lives and to their hopes for their families. Educational opportunities have supported the rise of the African middle class, the professional cadre of young people who are now willing and able to contribute to Africa's future prosperity. Provision of health services means that millions are now receiving the HIV treatment they need, and that millions of preventable deaths have been avoided. Improvements in economic management mean that trade, and regional trade, can increase, stimulating economic growth and providing millions with the opportunities to lift themselves out of poverty.
However, this progress is not reflected in the other two pillars of the index. Declines appear in what could be termed the political side of governance, namely rights, safety, and rule of law. These issues too are about people's lives. We are all too familiar with the drastic consequences of corruption, dysfunctional legal systems, and insecure and unsafe environments.