UNITED NATIONS -- The United States, the world's largest international aid donor, is among the worst at promoting the independence, impartiality and neutrality of humanitarian aid deliveries to needy populations, according to a survey by a Madrid, Spain-based group that monitors donors' performance.

The Development Assistance Research Associates (DARA) Humanitarian Response Index 2008 measures how effectively the world's 23 largest donors deliver aid. The United States ranked 15th in overall effectiveness and only 13th in the level of generosity measured by the size of its economy. But it ranked near the bottom, 22nd, when it came to adherence to principles and guidelines established by the Organization for Economic Cooperation and Development to ensure that political considerations don't exclude worthy recipients of aid.

DARA's findings reflect what it called the U.S. use of humanitarian assistance to achieve military or political goals in eight crisis zones the group studied, including Afghanistan, Colombia and the Palestinian territories.

The "assessment challenges the view of the United States -- deeply embedded in the American psyche and regularly reinforced in the rhetoric of public officials -- as the world's pre-eminent humanitarian actor, the paragon of global compassion," retired Tufts University professor Larry Minear wrote in the report.

Silvia Hidalgo, DARA's executive director and co-founder, urged President-elect Barack Obama to improve the U.S. approach. "American leadership in the field of humanitarian relief would improve the perception that people around the world have of the United States and would also inspire other donor countries to do their best on behalf of the world's least fortunate," Ms. Hidalgo said.

DARA's survey is based on interviews with more than 350 humanitarian aid agencies in 11 crisis areas -- Afghanistan, Bangladesh, the Central African Republic, Chad, Colombia, Congo, Nicaragua, the occupied Palestinian territories, Peru, Sri Lanka and Sudan. Sweden, Norway and Denmark were the highest performers, while France, Austria, Italy, Portugal and Greece received the lowest marks.