The study looked at how immigration policies in different countries affect the economic success of immigrants. Some countries aim to attract highly-skilled immigrants, while others focus on low-skilled workers. The researchers compared countries like Ireland and the UK, which attract skilled immigrants, with Southern European countries like Italy, Spain, and Greece, which have more open policies. They found that immigrants in countries with selective policies have better chances of finding higher-quality jobs. Overall, the study suggests that immigration policies play a significant role in immigrants' economic integration and success.