In a recent working paper Thomas Huddleston and Maarten Peter Vink demonstrate that the different dimensions covered by the MIPEX indicators all tend to correlate strongly with naturalization policies. A country tough on naturalization tends to be tough on other aspects of immigration and integration policies.
While it didn’t make a direct reference to this debate, my 2011 working paper on the reliability of the MIPEX as a scale fully supports this. In this working paper I show that all MIPEX indicators combined are a reliable scale, but also highlight redundancies. These findings actually prepared my recent post on remastering MIPEX indicators depending on the research question.