This question is interdisciplinary between economics and politics, but I suspect the answer lies more in politics and history than in economics, which is why I decided to post it here.

Looking at the list of African countries by Human Development Index, one notable feature is that small African island nations seem to do better than the ones located on the continent (or than Madagascar, the one large African island nation).

Out of 55 African countries (including Western Sahara, excluding dependencies), the HDI classification is:

Category Number of island nations Number of continental nations
Very high 1 (Mauritius) 0
High 1 (Seychelles) 6
Medium 3 15
Low 1 (Madagascar) 31

The two African countries with highest development, Mauritius and Seychelles, are small island nations. 31 out of 32 nations with the lowest human development are continental nations. 4 out of 5 small African island nations are among the 25% best performing ones when going by HDI. Cabo Verde and Mauritius are also among the best African nations on the Democracy Index, where 2 out of 3¹ ranked island nations score above 0.7, something only 2 out of 37 ranked continental countries achieve.

I think the difference is too large to be attributed to chance. What might cause this discrepancy? It doesn't appear in wealthier parts of the world. In the Pacific, small island nations do not outperform their continental neighbours, whereas their performance in the Caribbean has a huge variability. Only in Africa does there seem to be a clear difference between island and non-island nations.

¹ São Tomé and Príncipe and Seychelles are not listed on the Wikipedia article on the Democracy Index).

  • 3
    You missed Madagascar, which is ranked "low" in the HDI and is in the "hybrid" category at rank 80 in the democracy index.
    – ccprog
    Commented Mar 3, 2023 at 14:20
  • @ccprog True, I should have specified "small islands".
    – gerrit
    Commented Mar 3, 2023 at 15:59
  • 13
    The null hypothesis is that it's pure chance. Small nations always fluctuate more wildly than larger ones in their properties. Well performing small island nations could just be lucky. Also the number of small island nations is relatively low. Not sure if the performance difference is statistically significant. But if it is, one factor might be tourism. People are crazy about spending vacations on a small island, for whatever reason. Commented Mar 3, 2023 at 19:23
  • 5
    @Michau But that hypothesis test doesn't reflect the unequal sized binning, treating each country as one data point regardless of population or size, which isn't an appropriate assumption for understanding HDI trends, and it also ignores the categorization issues that, for example, treat as country like Mauritius, which is more South Asian than African as an African country.
    – ohwilleke
    Commented Mar 3, 2023 at 20:07
  • 2
    I just wonder whether some of this can be explained by the respective domestic situations. In contintental Africa the national borders still follow the old colonial borders rather than the possibly more stable tribal borders. Particularly on a small island there may be just one (dominant) tribe, not several factions vying for power, leading to continued unrest jarring economic development. I may be wrong, but I think that the shadows of the colonial era still loom large in some regions. Commented Mar 5, 2023 at 8:53

2 Answers 2



You don't really need anything more than random chance and the statistical anomaly that flows from specifying that the island nations be "small" to explain the pattern observed, even though proximity to the ocean and current and historical ties to areas outside of Africa are actually probably also factors.

Taken together, this suggests that there is no really special connection between the physical geography consideration of a country being a small island nation and its HDI. This is despite the fact that focusing on "small" island countries, treating each country as a single data point statistically, and making decisions to include countries within the data set that it is fairly arbitrary to classify as "African" appears to create a much stronger statistically significant relationship to this factor than a wider view of the facts with a richer context for the data points would support.

Coarse v. Fine Grained Statistics

Simply put, if you broke up Africa into units of comparable size to those of the "small" islands, some of those units would have a relatively high HDI against an overall fairly low background. Economic development tends to get in virtuous cycles in city sized areas.

You can see this on this map, which shows wide variation in HDI within different regions in many continental African countries (although even these subunits almost all have greater populations and areas than small African islands leaving them still more coarse grained):

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It is also worth noting that the map does not have fine grained subnational details for Algeria, Libya and Egypt, which is misleading. Algeria and Libya actually have significant disparities between the coast (where the vast majority people live and the major cities area located) and the deep Saharan interior (where the less Arabized Berber population and other ethnic populations that have historically been Saharan nomadic herders predominate).

Likewise, economic development in Egypt is highly disparate between the Nile basin and the remainder of the country. Egypt's Saharan and near Saharan west outside the Nile basin is actually quite challenged compared to the Nile basin.

If the North African statistics were more fine grained, more of North Africa would have a "medium" rather than "high" HDI index.

But, if you immerse the pockets of high HDI in continental Africa in whole larger countries, this gets diluted statistically. And, most mainland African countries are larger than most island nations in Africa, with Madagascar being the exception.

Nigeria, for example (which has 225 million people speaking 525 languages, and a land area greater than California and Texas combined) has an exceptionally wide spread between its interior North with an extremely low HDI and its coastal South which has areas on the high end of the medium HDI range (and would have a few pockets of high HDI within its major cities if one were to be even more fine grained than this map in its statistical analysis).

Similarly, for example, Namibia's has one pocket of high, rather than medium or low economic development in Erongo, which has one of the highest HDI indexes in sub-Saharan Africa outside of country of South Africa. But, at the coarse grained national level, this is invisible and diluted by areas of medium and low HDI indexes in Namibia.

In the same way, is you were to single out Chicago from Illinois, or Philadelphia from Pennsylvania, both of those areas would be much more economically prosperous than the states as a whole and would rank higher in a per capita GDP measure than the states themselves do because the high points are diluted.

The same phenomena in the United States is one of the reasons that, for example, the District of Columbia, which consists only of the central city of a larger metropolitan area, is often at an extreme ranking on many social science statistics in the United States (e.g., having the oldest average ages of marriage).

Proximity To The Ocean Helps. Why Is This So?

Proximity to the ocean (which, of course, coastal areas in continental Africa have to the same extent as island nations) is indeed a factor as well, for reasons that have a complex history rooted in maritime trade with European colonial powers.

Through the 1500s, Africa didn't lag far behind the rest of the world economically, educationally, technologically, or militarily, and interior regions of West and Central Africa were more prosperous than coastal regions (exemplified by places such as Timbuktu) because of the role of these regions in facilitating trans-Saharan trade.

But, this changed when maritime trade conducted by European colonial powers largely superseded trans-Saharan trade. Abel Gaiya, writing from Nigeria in a February 9, 2023 article in the Republic, recounts at length the complicated historical sequence of events that led African economic prosperity to flip from interior to coastal regions in West and Central Africa.

This suggests, contrary to the analysis in the answer by Tyler mc, that the key economic benefit to ocean access is access to maritime trade and investment, rather than access to particular natural resources like seaweed. Lots of continental African countries have immense high value natural mineral resources, access to the ocean, and tropical weather as pleasant for tourism as island destinations in the Caribbean, Polynesia, and the Indian Ocean. Yet most of these countries remain poor and have low HDI rankings.

This said, it would also be wrong to omit the one exception that proves this rule, which is Namibia. The population of Namibia, and it urban and economic development, is overwhelming inland of its coastal mountain range, rather than on its coast. Namibia's one pocket of high, rather than medium or low economic development is similarly in the center of the country, rather than on its coast.

Obviously, of course, it is also true in the larger global context, that while 40% of the world's people live within 60 miles of a coast, there are economically prosperous areas with higher HDI that are far from any coast. Denver, Colorado, the Czech Republic, the Australian Capital Territory, and the federal district of Brazil, for example, come immediately to mind.

Are These Really "African" Island Nations?

As a final point, classifying the Indian Ocean island countries of Mauritius and Seychelles, and the Atlantic Ocean country Cabo Verde and São Tomé and Príncipe as "African nations" is rather arbitrary.

Since the lynch pin of the "small island nation" hypotheses in the question depends heavily on these four countries, their marginal relationship to continental Africa casts doubt upon this hypothesis.

The classification of Comoros as a small African island nation is not arbitrary, but needs to be considered in light of the near total replacement of its population between 1790 and 1820, which is a comparatively recent anomaly that is unprecedented anywhere else in this set of 55 countries. Comoros also just barely crossed the line from having a low HDI to a medium one in the last fifteen years, after a 48 year history of independence that has included at least fifteen coups and other deep barriers to economic development.


Two-thirds of the 1.3 million people of Mauritius are ethnically Indian and the plurality religion of the country is Hindu. Only 28% of the people of Mauritius are "Creole", which is a mix of former slaves with East African Bantu roots, and former slaves with Malagasy roots who are a mix of East African and Southeast Asian ancestors - in both cases with a smattering of European and South Asian ancestry as well. If one had to associate Mauritius with one continental area based upon its economic and cultural ties, India would be a better fit than Africa.


The hundred thousand people of Seychelles (about the same population of a single block in Manhattan and a third of the population of Iceland) has deep influences from Southeast Asia, Europe, and Arabia historically, as well as Africa via the Southeast Asian-East African hybrid people of Madagascar. Culturally and ethnically, the Seychelles are neither here nor there.

The Seychelles were uninhabited prior to about 1000 CE when Southeast Asian sea farers arrived, and people of African origins did begin to arrive there until later in the 1600s.

Seychelles was uninhabited throughout most of recorded history. Tombs on the island, visible until 1910, are the basis for the scholarly belief that Austronesian seafarers and later Maldivian and Arab traders were the first to visit the archipelago. Vasco da Gama and his 4th Portuguese India Armada discovered the Seychelles on 15 March 1503; the first sighting was made by Thomé Lopes aboard Rui Mendes de Brito. Da Gama's ships passed close to an elevated island, probably Silhouette Island, and the following day Desroches Island. They mapped a group of seven islands and named them The Seven Sisters. The earliest recorded landing was in January 1609, by the crew of the Ascension under Captain Alexander Sharpeigh during the fourth voyage of the British East India Company.


Cabo Verde

Classifying the Atlantic Ocean island nation of Cabo Verde (which has a population of 562,000 people) as "African" is likewise arbitrary. As explained at the link:

Before the arrival of Europeans, the Cape Verde Islands were uninhabited. They were discovered by Genoese and Portuguese navigators around 1456. . . In 1462, Portuguese settlers arrived at Santiago and founded a settlement they called Ribeira Grande. . . .The original Ribeira Grande was the first permanent European settlement in the tropics.

Cabo Verde has many people who are freed slaves of African origin, as a consequence of the island chain serving as a hub of the 16th to 18th century slave trade when it was a Portuguese colony. But in terms of human geography, it is no more African than say Jamaica, which has a large population of African origin for the same reason.

Cabo Verde did maintain stronger African ties, with its movement for independence from Portugal from 1956-1975 organized by the African Party for the Independence of Guinea and Cape Verde (PAIGC) which united an African Portuguese colony with Cabo Verde. But its history and people really have more in common with the Iberian colonies in the Americas and the Caribbean than it does with the peoples of continental Africa.

São Tomé and Príncipe

The 223,000 people of São Tomé and Príncipe in the Atlantic Ocean live in a country with a history strongly parallel to that of Cabo Verde, as a previously uninhabited island, discovered by Portuguese explorers in the 1400s and run as a colony economically reliant upon the African slave trade for centuries before its mostly African origin population rose up with a mainland African alliance and eventually secured independence in 1975.

For the same reason that it is somewhat arbitrary to classify Cabo Verde as an African island country, it is somewhat arbitrary to treat São Tomé and Príncipe as an African island country.


Comoros is a small island country with 851,000 people with a medium HDI between Madagascar and the continent of Africa which shares a largely common history with Madagascar up through its first encounter with Portuguese explorers in 1503, and was a trading post for Indian Ocean Arabian seafarers after early contact with Austronesian sea farers from Southeast Asia ceased.

The historical population of Comoros, however, was almost complete replaced in the time period from 1790 to 1820 in a little know historical African genocide:

In the last decade of the 18th century, Malagasy warriors, mostly Betsimisaraka and Sakalava, started raiding the Comoros for slaves and the islands were devastated as crops were destroyed and the people were slaughtered, taken into captivity or fled to the African mainland: it is said that by the time the raids finally ended in the second decade of the 19th century only one man remained on Mwali. The islands were repopulated by slaves from the mainland, who were traded to the French in Mayotte and the Mascarenes. On the Comoros, it was estimated in 1865 that as much as 40% of the population consisted of slaves.

France first established colonial rule in the Comoros by taking possession of Mayotte in 1841 when the Sakalava usurper sultan Andriantsoly [fr] (also known as Tsy Levalo) signed the Treaty of April 1841, which ceded the island to the French authorities.

Unlike the other four cases discussed in this section, it is not arbitrary to call both the original and the replacement populations on these islands a very short distance from the Indian Ocean coast of Africa a small African island nation.

But, like the other four, it does have a highly disrupted history which is really for all practical human geography purposes, shorter than any of the others.

It is also worth noting (from the same source) that:

[Comoros] has experienced more than 20 coups or attempted coups, with various heads of state assassinated. Along with this constant political instability, it has one of the worst levels of income inequality of any nation, and ranks in the worst quartile on the Human Development Index. As of 2008, about half the population lived below the international poverty line of US$1.25 a day.

Comoros is just barely over the line between low HDI (0.550 and less) and medium at an HDI of 0.558 in the link cited in the question and is at close to the bottom of the medium ranked entries on that list. But this improvement from low to medium appears to be because it turned itself around slightly only in the last fifteen years, rather than due to any benefit foreordained or strongly biased by its status as a small island country.

  • Arbitrary — maybe, but they're members of the African Union, and closer to Africa than to any othe continent.
    – gerrit
    Commented Mar 3, 2023 at 22:34
  • 9
    @gerrit Sheer physical proximity isn't all that relevant. Papua New Guinea is closer to New Zealand than Britain, but we wouldn't expect their economies or HDI to be more similar to that of the Papuans or to the people of mainland Asia for that reason alone. Every country in continental Africa has been continuously inhabited (and prior to European colonization, ruled) by people who are ancestors of the current residents for many thousands of years.
    – ohwilleke
    Commented Mar 3, 2023 at 23:30
  • 3
    With regard to the Comoros, it should be noted that France is investing quite a bit in the archipelago. It's financed building hospitals on the 3 non-French islands, for example, in an attempt to staunch illegal immigration to Mayotte. The success is... mitigated, and it's likely that quite a bit of the money is "lost" in the process, but it may nonetheless help boost the development of the archipelago. (Source: visited Mayotte, and the dispensaries in the North of the island were illegal immigrants come to get treated before being shipped back) Commented Mar 5, 2023 at 12:08

This general trend in terms of a stable economy and HDI can be partially due to the benefits of living near the ocean. 90% of trade goods are delivered by sea, so living on an island or near the sea creates an advantage in terms of trade & makes it easier to get involved in industries like shipping and shipbuilding. You can make ports for international trade and even charge merchants for docking in the ports, which can help boost your economy. You also have easy access to seafood for food & trade, no direct land borders with nations that might want to take resources, the fact that island countries have been more stable historically than continental states (this applies to the whole world, not just Africa) & usually only had to worry about naval superpowers, and being an island nation means you can have more tropical island/ocean tourism too. You can also, as an island nation, farm seaweed which can be used for food, medicine, fertilizer for crops, livestock feed, and even biofuels in the near future. One of the top seaweed farming regions in the world is Zanzibar, a semi-autonomous island in Africa.

Islands are in the middle of the ocean and easier specifically for establishing deep water ports and establishing ports for trade routes where hugging the coast of the African continent would take longer than using a port in the middle of the ocean, especially since timing is very important with shipping. Also, while someone has brought up the history of Comoros that there were over 20 coups, but the key here is that island nations are generally more stable throughout ALL OF HUMAN HISTORY. One exception does not break the general rule. Also, while generally prosperous for various reasons, island nations are not immune to human politics. A lot of problems on Comoros seem to date back to a series of political struggles that date back to the Cold War & battles between traditionalists & socialist revolutionaries, something that would affect any nation's ability to take full advantage of any pros they have by being an island nation.

  • Is it better to live in Minnesota or California? +1. One of those is the fifth largest economy on the planet, the other is Minnesota....
    – Mazura
    Commented Mar 4, 2023 at 22:24
  • 2
    @Mazura Hm? Minnesota has a higher HDI than California, and many US states and territories with relatively low HDI are coastal (U.S. Virgin Islands, South Carolina, Louisiana, Kentucky, Alabama, Northern Mariana Islands, Mississippi, Puerto Rico, American Samoa), so not sure if it works in the US — on the other hand, the town farthest from the ocean in the USA is also (one of the) poorest (96% below poverty line, median male income of $0).
    – gerrit
    Commented Mar 5, 2023 at 18:02

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