I'll clarify, then, with an analogy.  I used to work in the area of employment testing.  One of the goals of that industry is to be able to identify candidates who will add value to the organization and perform well.  But few employment tests demonstrate fabulous prediction of performance, largely because every hire has to grow into the job.  Few, if any, will be "ready" first thing Monday morning.

Similarly, the notion that we could identify immigrants, via some test, who are "ready to go", presumes that citizenship qualities are reliably measurable in an all-or-none fashion; that there could be a test with high predictive validity.  But if we can't even predict whether someone is going to work out well as a shoe salesman or cashier, how could we predict that someone is going to be a citizen worth having?  Our prisons are full of Canadians who could pass such a "values" test.  Fat lot of good it does us, eh?