The annual report measures how domestic policy in the world's 27 richest countries affects quality of life and development in poorer countries.
It looked at seven different themes: aid, economy, technology, environment, trade, security, and migration. Then, the authors ranked each country in a 'Commitment to Development' index, with Sweden coming out on top and last year's leader Denmark relegated to second place.
“A good policy for development is about much more than aid,” said Masood Ahmed, president of CGD, in a statement.
“Although it's important, politicians in rich countries must evaluate how all their decisions, from refugee policy to copyright, help or hinder developing countries,” Ahmed continued.
Sweden's high ranking was due to a strong performance in environment (in which it was ranked 2nd of all 27 countries), aid (3rd), trade (5th) and above all migration, in which it achieved the top ranking. The report also highlighted that Sweden had accepted the highest proportion of refugees of any of the countries included, except from Germany.
“The Swedish aid programme is one of the best in the whole world, and that applies to quality and quantity. Sweden is also very good when we look at migration policy and the environment,” Anita Käppeli, one of the report's authors, told Swedish radio Ekot.
“When we look at integration policy, at least on paper we see that Sweden's policy is very good. But it seems as if the feeling among the population is different; that it doesn't feel like it's working,” she added.
The report also noted that Sweden only approved 35 percent of asylum applications, below the average for the countries included in the index and the lowest acceptance rate in Sweden over the past five years.
The think tank highlighted further possible areas for improvement in Sweden, noting: “It has room for improvement on security, given its substantial arms exports and low contributions to international peacekeeping and sea lanes protection.”
In security, Sweden was ranked only 20th, and it also received lower scores for economy (11th) and technology (13th).