For a good overview of the debate see Bloemraad, I. (2011), ‘The Debate Over Multiculturalism: Philosophy, Politics, and Policy’, in The Online Journal of the Migration Policy Institute. http://www.migrationpolicy.org/article/debate-over-multiculturalism-philosophy-politics-and-policy

For the arguments of one of the key proponents of multiculturalism discussed in the chapter see Kymlicka, W. (2012), Multiculturalism: Success, Failure, and the Future, Washington, DC: Migration Policy Institute. http://www.migrationpolicy.org/research/TCM-multiculturalism-success-failure

The Multiculturalism Policy Index is available here
http://www.queensu.ca/mcp/

For critique of multiculturalism from a left-wing position see:

Malik, K. (2015a), ‘The Failure of Multiculturalism: Community Versus Society in Europe’, Foreign Affairs, March/April Issue
https://www.foreignaffairs.com/articles/western-europe/failure-multiculturalism

Malik, K. (2015b), ‘Assimilationism vs Multiculturalism’.
https://kenanmalik.wordpress.com/2015/01/12/assimilationism-vs-multiculturalism/

The Casey Review: a review into opportunity and integration
This report sets out the findings of a review by Louise Casey into integration and opportunity in the UK’s most isolated and deprived communities. It can thus be seen as an evaluation of multiculturalist policy
https://www.gov.uk/government/publications/the-casey-review-a-review-into-opportunity-and-integration

Useful thinktanks that focus on migration and issues around cultural diversity and cohesion:

The Migration Policy Institute (MPI) http://www.migrationpolicy.org/
“MPI provides analysis, development, and evaluation of migration and refugee policies at local, national, and international levels. It aims to meet the demand for pragmatic and thoughtful responses to the challenges and opportunities that large-scale migration, whether voluntary or forced, presents to communities and institutions in an increasingly integrated world.”

British Future http://www.britishfuture.org/about/what-we-do/
“British Future is an independent, non-partisan thinktank seeking to involve people in an open conversation, which addresses people’s hopes and fears about identity and integration, migration and opportunity, so that we feel confident about Britain’s Future”

The Migration Observatory
http://www.migrationobservatory.ox.ac.uk/
“provides impartial, independent, authoritative, evidence-based analysis of data on migration and migrants in the UK, to inform media, public and policy debates, and to generate high quality research on international migration and public policy issues.”