Prometric and the IELTS partners have just published a concordance study comparing the CELPIP and IELTS-General tests.
It is a very nice study. I just want to mention that of the 1089 participants, seemingly not a single one earned an IELTS writing score of 9.0. Two participants earned a score of 8.5. This is the fourth concordance study in a row involving IELTS in which not a single person reported a perfect writing score. I don’t know if that’s meaningful, but it amuses me.