Referring to the Can Do discussion started by Michele’s response to the “This Is What We Are Faced With” post, in one succinct paragraph, Eric Herman has written something very important and really brilliant, in my opinion. In one paragraph, he has written a book:
The one thing we don’t want to do is abandon TCI, because a Can Do statement is “still not a valid reason for employing a method that is incorrect” . . . “Most language tests are based on the skill-building hypothesis; they test grammar, vocabulary, spelling, etc. It seems obvious to many people that the best way to study for these tests is to study grammar, vocabulary, spelling, etc. The research, however, tells us differently: Students in classes with more comprehensible input do better on such tests than those in traditional classes” . . . “We must, however, realize that it is our professional responsibility to teach according to our convictions about how people acquire language.” (Krashen, 2004)
http://www.sdkrashen.com/content/articles/why_support.pdf