I just came across an old-ish article in The Huffington Post about teaching critical thinking in schools:
Dr.Christianna Alger states that asking the right questions may build a critical thinking classroom. (Many of the times you see baffled looks from students is due to the question not being clearly stated or it is not the correct question for the answer that you believe is right.)
CLARITY. Can you state that in a different way? Can you elaborate on what you said? Can you give an example? Is there another word or phrase that communicates the problem?
ACCURACY. How do we check to see if that statement is valid? How do we know it is correct? Where did you get the information? How can we verify or test it? (This is less of a problem when the sources are known and controlled by the teacher or district, but does it allow for challenges?)
DEPTH. What factors make this a difficult problem? What are some of the complexities inherent in this problem? (We tend to go towards simple answers.)
RELEVANCE. How does that relate to the problem? How does that help us with the issue?
FAIRNESS. Do you have a vested interest in this issue? Are you sympathetically representing the relevant viewpoint of others? (This gets to the heart of my objection in calling it critical thinking. Is the student able to present a radically different viewpoint without it conflicting with what the teacher wants, believes is correct, or will accept?)