Looking at the history of Ghana relative to many post-colonial African states, it appears to be quite a successful and stable nation-state, both politically and economically, compared to many other post-colonial African nations. My hypothesis is that Ghana's success may to a large extent be the result of its being administered by the British during its colonial period, rather than the French, Belgians, or Portuguese, etc: Perhaps British colonies evolved into more stable, economically successful, independent states than their counterparts who are former French, Portuguese colonies, etc. A friend of mine from Ghana confirmed my hypothesis, but had no solid evidence to back it up.
A brief survey of some African countries seems to confirm my hypothesis: I compared the history of Ghana (formerly Gold Coast under the British) with that of the Democratic Republic of the Congo (formerly "Belgian Congo"), Republic of the Congo (formerly "French Congo"), and Angola (formerly a Portuguese colony). Compared to Ghana, the non-British colonies have been plagued with long and violent civil wars and political instability, which seriously impacted their economic growth and viability,
More research into the the success and stability of other former British colonies relative to their non-British counterparts also seems to back up such a theory: For example Jamaica, under the Brits from 1655 until 1958, and Trinidad/Tobago, administered by the Brits from 1889 until 1958 - in comparison to countries such as Cuba (Spain), Haiti (France), and the Dominican Republic(France/Spain/USA for a brief periods).
But my research here is admittedly quite superficial. Does historical analysis confirm or contradict my hypothesis that former British Colonies have been more successful as post-colonial states? More generally, can we find a pattern of success in the independent states that corresponds to their former colonial administrators (not necessarily the British)?
Although this question is admittedly complex, it can be answered with empirical analysis. A capable historian or economist should be able arrive at a clear conclusion, although not all will come to the same one, as is the case with any complex question. It requires extensive research to arrive at an accurate, well documented answer, but the answer itself can be quite concise and empirically based.
To side-step the issue of when to 'stop the clock' regarding measurement of success (today; five years ago; 10 years after independence....) the best answer might take into account the sum total of a former colony's history, such that a country like Angola, now quite successful, might not be considered successful relative to Ghana, considering the long and bloody civil wars that dominate much of Angola's history. But not being a historian or economist, I am not really the one to decide on the metrics: I turn to the Historians and experts among us for an appropriate way to quantify and answer this question.