1. The King Baudouin Foundation and the Migration Policy Group have piloted a new type of European survey whose aim is to increase the voice of immigrants in the development of integration policies. 2. Policy actors can learn about the different integration policies (see Migrant Integration Policy Index) and different integration situations (see EU migrant integration indicators) but they do not know about the implementation and effects of these policies on the integration situation. 3. This knowledge gap can be overcome by a representative survey among immigrants—by directly asking about policy impact and by formulating the survey so that the results are comparable and easy-to-use by civil society. Unfortunately, immigrant surveys tend to be rare, general, and non-comparable across countries. 4. The Immigrant Citizens Survey is the first transnational survey that is directly relevant for policy-makers in many areas of integration at local, national, and European level. 5. This survey of non-EU-born legal immigrants was large enough to capture the insights of the people that are living through the policies being discussed across Europe. Its design was inspired by “needs assessments,” “client feedback” or “citizens surveys”, which search for solutions to address societal problems and improve overall satisfaction in society. Immigrants were asked for their assessment of whether policies are relevant, implemented, used, and have an impact on their own lives. 6. Though integration is local, many policies are national and, increasingly, affected by EU law and European trends. The way that national and EU policies are implemented at local level may change from city to city. 7. To evaluate which policies are improving integration, the same types of immigrants were asked the same questions in the same way across cities and countries. 8. Eighteen major European general surveys from the past five years were reviewed and several questions were used in ICS in order to compare the experiences of surveyed immigrants in these cities to the general public in the country.