Opinions

 The structure of a poem is more factual than a matter of opinion. Students will tell me that in their opinion, there is no rhyme in this poem--when the poem actually has a rhyme scheme. I don't care whether I agree with a student's interpretations. They can still do fine even if they don't happen to agree with me. The reason is that we, the professors, disagree with one another all the time about interpretations. It would be unfair to penalize a student for not reading my mind. But it is an objective fact that viene rhymes with muerte (assonantal rhyme, according to the rules of Spanish prosody). 

I end up wanting to teach them very basic things. Which words rhyme with which other words, not to call every work of literature a "cuento" or, even worse, a "cuenta." That the word tema is masculine in Spanish. Not to center every line of a poem. 

Accurate statements of fact are very difficult. My friend wrote an article about a small town in Kansas for AAA magazine. An editor changed the wording enough to introduce 4 or 5 factual errors in a short piece. My friend had to then correct the editor so that these mistakes wouldn't show up in the final product. We've all seen journalism about things we actually know about, and notice how inaccurate it tends to be. Of course, journalism about things we don't know about will also have the same errors, but we won't be in a position to correct them. 

Consider the student who takes basic factual information from a wiki. The student must read the source, summarize it accurately, cite the source, integrate that information into his or her own paper in a meaningful way. I get tired of reading from my students how Lorca is writing about a dictatorship that did not yet exist during his lifetime.