According to a 2014 study, the Haitian economy stagnated due to a combination of weak state power and adverse international relations. The authors write:For the newborn ‘Negro republic’, it was hard to become recognised as a sovereign nation state, it was difficult to form strategic alliances, to get access to foreign loans, and to safeguard trade interests, and it was overloaded with debt under threat of external violence (the French indemnity). Self-chosen isolation, for instance by prohibiting foreign landownership, further reduced the choice set of successive Haitian administrations. When opportunities for export-led growth opened up in the late 19th century, the odds were stacked against Haiti.Under President René Préval (President from 1996 to 2001 and from 2006 until 14 May 2011), the country's economic agenda included trade and tariff liberalization, measures to control government expenditure and increase tax revenues, civil-service downsizing, financial-sector reform, the privatization of state-owned enterprises, and the provision of private sector management contracts, or joint public-private investment. Structural adjustment agreements with the International Monetary Fund, World Bank, Inter-American Development Bank, and other international financial institutions aiming at creating necessary conditions for private sector growth, have proved only partly successful.