Currently, student visas are not included in the 4.4% target, so a study would be needed to look at the refusal rate. However, it clearly doesn't help to achieve the target.
But I would add that, last year, a new path from temporary residency to permanent residency opened up . Seven thousand francophones outside Quebec have taken advantage of that path to permanent residency. That is a significant number of people who could stay in the country and help to achieve the 4.4% target.