5. Sierra Leone
> GCI score: 3.01
> GDP per capita: $613 (11th lowest)
> Debt as a pct. of GDP: 44.5% (68th highest)
> Pct. of residents using Internet: 1.3% (4th lowest)
> Biggest problem in doing business: Access to financing

Sierra Leone was one of only three other countries studied by the WEF to have a negative gross national savings score in 2012. It also had some of the worst inflation rates in the world, with consumer prices rising by 13.8% in 2012, higher than all but eight other countries. In terms of health care, Sierra Leone consistently ranks close to the bottom. Malaria is relatively common, and there are more than 700 cases of tuberculosis per 100,000 people, a rate surpassed by only South Africa and Swaziland. Sierra Leone has the worst infant mortality rate, and the life expectancy at birth is just 47.8 years, the worst out of the 148 countries studied.

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4. Yemen
> GCI score: 2.98
> GDP per capita: $1,377 (31st lowest)
> Debt as a pct. of GDP: 46.7% (55th highest)
> Pct. of residents using Internet: 17.4% (42nd lowest)
> Biggest problem in doing business: Police instability

When Yemen residents were asked to identify the most problematic factor for doing business, most respondents said police instability. Inadequate supplies of infrastructure and corruption followed closely as obstacles for conducting business. Yemen’s business transactions are plagued by bribes and under-the-table dealing, while the legal system cannot be relied on for help. Yemen’s government also is considered to be excessively wasteful, and public funds are frequently misused. Violence in the region and the presence of extremist groups have made it difficult for residents to innovate or accomplish very much at all in the way of business. The business costs of crime, violence and terrorism were judged to be higher in Yemen than most other nations.

3. Burundi
> GCI score: 2.92
> GDP per capita: $282 (2nd lowest)
> Debt as a pct. of GDP: 32.0% (40th lowest)
> Pct. of residents using Internet: 1.2% (3rd lowest)
> Biggest problem in doing business: Access to financing

Burundi did less to promote economic efficiency than any other nation in the world, according to the WEF. Access to financing and corruption were by far the most selected problematic factors for doing business; the availability of financial services in Burundi was ranked among the worst in the world. Burundi is the world’s second-poorest nation in terms of GDP per capita, behind only Malawi. Residents of Burundi said their judiciaries were heavily influenced by members of government, more than those in almost any other country. The poor reliability of Burundi’s police services — second worst out of 148 countries — and low scores for ethical behavior in Burundian businesses make doing business in the country extremely difficult.

2. Guinea
> GCI score: 2.91
> GDP per capita: $519 (7th lowest)
> Debt as a pct. of GDP: 43.0% (74th highest)
> Pct. of residents using Internet: 1.5% (6th lowest)
> Biggest problem in doing business: Corruption

The quality of infrastructure in Guinea is exceptionally bad. The country has one of the least reliable electrical supplies in the world, one of the lowest numbers of fixed telephone lines per 100 residents and some of the worst roads in the world. Its health care is not much better. In 2010, there were nearly 38,000 incidents of malaria for every 100,000 people in the country, the most severe locus of malaria cases in the world. Poor health and primary education mean workers are sick more often and less likely to adapt to new work environments.

Also Read: The Best Economies in the World

1. Chad
> GCI score: 2.85
> GDP per capita: $1,006 (23rd lowest)
> Debt as a pct. of GDP: 34.5% (53rd lowest)
> Pct. of residents using Internet: 2.1% (8th lowest)
> Biggest problem in doing business: Access to financing

Chad has the worst infrastructure in the world, according to the WEF. Electricity, fixed and mobile phone lines, and transportation options are all extremely limited in the sub-Saharan nation. Diversion of public funds also is considered a major problem in the country, as is the weak protection of citizens’ property rights. Chad also ranked as the worst nation for illicit payments and bribes. No country received a worse grade than Chad in health and primary education. The nation had more than 36,000 cases of malaria per 100,000 residents in 2010, and a life expectancy at birth of less than 50 years in 2011.

Editor’s Note: A previous version of this article noted that GDP statistics used by the World Economic Forum reflected Purchasing Power Parity exchange rates. In fact, GDP figures are expressed in current dollars.