I see a common theme in this and your other comment[0]. In my experience, however, evaluations from students have next-to-nothing to do with how much the students have or have not learned, and that is the point of the linked study[1]. Quoting:

    > Controlled, randomized experiments find that
    > SET ratings are negatively associated with
    > direct measures of effectiveness. SET seem
    > to be influenced by the gender, ethnicity,
    > and attractiveness of the instructor. 

The other link[2] says:

    > We find that teacher quality matters substantially
    > and that our measure of effectiveness is negatively
    > correlated with the students’ evaluations of professors.

Both these formal studies are at odds with what you seem to be saying.

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[0] https://news.ycombinator.com/item?id=9445924

[1] http://www.stat.berkeley.edu/~stark/Preprints/evaluations14....

[2] http://www.sciencedirect.com/science/article/pii/S0272775714...