Partial credit for right and wrong answer?

[paddington_bear]

Let's say the question on the exam is....."What rights did the Civil Rights Act of 1957 protect?" And the correct answer is "Voting rights." But the student responds, "protected against segregation in public and government facilities and made it illegal to infringe on someone's right to vote."  Do you give the full credit because they gave the right answer? Or half credit because part of their response was wrong?

[onthefringe]

I usually try to take into account how wrong the answer is. Stream of consciousness "things I heard in class" that happen to include the right answer along with many wrong things get half credit (or less). Things that are generally right but have one "off topic but not egregiously wrong" statement might get somewhere between 3/4 and full credit.

Your example is outside my field, but given that the act also created the Commission on Civil Rights (I think?) I might go easy on the part of the answer that's wrong. But I know you are probably trying to make up a semi-equivalent version of the real question/answer, so this might not be relevant.

[dismalist]

How about zero credit?

Suppose this were a multiple choice exam. And one possible answer is "protected against segregation in public and government facilities and made it illegal to infringe on someone's right to vote." Another is "made it illegal to infringe on someone's right to vote". A third might be "made it illegal to discriminate by race, sex, and national origin". A fourth might be "legalized same sex marriage".

There is only one correct answer.

Think what would happen [has happened] when partial credit is granted for an answer that contains the correct answer but is encumbered by incorrect answers. Students would write all kinds of stuff, with the more they wrote increasing their chances of getting partial credit evermore.

[paddington_bear]

How about zero credit?

Suppose this were a multiple choice exam. And one possible answer is "protected against segregation in public and government facilities and made it illegal to infringe on someone's right to vote." Another is "made it illegal to infringe on someone's right to vote". A third might be "made it illegal to discriminate by race, sex, and national origin". A fourth might be "legalized same sex marriage".

There is only one correct answer.

Think what would happen [has happened] when partial credit is granted for an answer that contains the correct answer but is encumbered by incorrect answers. Students would write all kinds of stuff, with the more they wrote increasing their chances of getting partial credit evermore.

Your example is a good one. And zero credit was my immediate response! If the correct answer is "only A," then "A and B" is not correct. But I don't think I have the energy to fight with/explain to the student why, although they wrote the right answer, they also included something that was incorrect, so they're not getting a point for that response.

[paddington_bear]

I usually try to take into account how wrong the answer is. Stream of consciousness "things I heard in class" that happen to include the right answer along with many wrong things get half credit (or less). Things that are generally right but have one "off topic but not egregiously wrong" statement might get somewhere between 3/4 and full credit.

Your example is outside my field, but given that the act also created the Commission on Civil Rights (I think?) I might go easy on the part of the answer that's wrong. But I know you are probably trying to make up a semi-equivalent version of the real question/answer, so this might not be relevant.

Oh god, on another question I'm running into students writing down as an answer something that they misheard or mis-wrote down in class. Actually, I don't think they misheard as much as half heard. They wrote down an answer for something that a student had given in class, but I explained in class why that wasn't the correct answer. Ugh. These students..... But I'm leaning toward not giving any credit because I do kind of consider the wrong part of the response "egregiously wrong." Desegregation didn't have anything to do with the CR of 1957.

[Hegemony]

I would give it half credit, since part of what they said was on target.

[dismalist]

Well, the exam question is a factual one. It must have a clear answer. Also, it must be important to listen properly in class.

Suppose it's a chemistry exam.

Q: How is it safest to mix sulfuric acid with water?

A1: Add some water to lots of sulfuric acid.

A2: Add some sulfuric acid to lots of water.

Anyone getting the wrong answer and doing it accordingly is going down the tubes. Now there's incentives to get the right answer!

This would really be a self=grading test. :-)

[marshwiggle]

How about zero credit?

Suppose this were a multiple choice exam. And one possible answer is "protected against segregation in public and government facilities and made it illegal to infringe on someone's right to vote." Another is "made it illegal to infringe on someone's right to vote". A third might be "made it illegal to discriminate by race, sex, and national origin". A fourth might be "legalized same sex marriage".

There is only one correct answer.

Think what would happen [has happened] when partial credit is granted for an answer that contains the correct answer but is encumbered by incorrect answers. Students would write all kinds of stuff, with the more they wrote increasing their chances of getting partial credit evermore.

Your example is a good one. And zero credit was my immediate response! If the correct answer is "only A," then "A and B" is not correct. But I don't think I have the energy to fight with/explain to the student why, although they wrote the right answer, they also included something that was incorrect, so they're not getting a point for that response.

This is why, for questions requiring regurgitation, multiple choice is the good way to go; not only can it be autograded, but it means these kinds of explicit situations can be given for students to choose from.

Keep the free-form answers to things where there isn't a predetermined correctly-worded response.

[Sun_Worshiper]

I'd give half credit.

[Caracal]

I usually try to take into account how wrong the answer is. Stream of consciousness "things I heard in class" that happen to include the right answer along with many wrong things get half credit (or less). Things that are generally right but have one "off topic but not egregiously wrong" statement might get somewhere between 3/4 and full credit.

Your example is outside my field, but given that the act also created the Commission on Civil Rights (I think?) I might go easy on the part of the answer that's wrong. But I know you are probably trying to make up a semi-equivalent version of the real question/answer, so this might not be relevant.

Oh god, on another question I'm running into students writing down as an answer something that they misheard or mis-wrote down in class. Actually, I don't think they misheard as much as half heard. They wrote down an answer for something that a student had given in class, but I explained in class why that wasn't the correct answer. Ugh. These students..... But I'm leaning toward not giving any credit because I do kind of consider the wrong part of the response "egregiously wrong." Desegregation didn't have anything to do with the CR of 1957.

Honestly, this is part of why I just do all essay questions. Students still write down all sorts of wrong things, of course, but I can assess how much it matters that they are wrong, rather than try to parse degrees of wrongness. If a student was writing an essay about divisions over tactics and goals in the Civil Rights movement following legislative victories and wrote "following the 1967 Civil rights movement.." gave that definition and then moved on to talk about other things, it's a pretty minor mistake. If the essay is about the interstate commerce clause and its role in the Civil Rights movement, it's a bigger mistake-although not disastrous in the context of an otherwise solid essay.

[Ruralguy]

Some sort of partial credit-- and I give partial credit on my STEM exams too, when part of the answer is correct, that is.

[paddington_bear]

This is why, for questions requiring regurgitation, multiple choice is the good way to go; not only can it be autograded, but it means these kinds of explicit situations can be given for students to choose from.

Keep the free-form answers to things where there isn't a predetermined correctly-worded response.

That's an interesting perspective. My exam was a mix of multiple-choice, short ID's/definitions - which this question was - and longer short answers. Students could bring in to the exam a notebook-size sheet of paper with all of the notes they wanted on both sides. (And there's no autograding, unless you just mean mindlessly checking that the right letter was circled. The exam was taken in class.) I thought that a simple regurgitation answer could easily be elicited as a simple ID question with a simple answer. Two words. "Voting rights." Or something like, "called for prosecution of people who impede voting rights." Especially since they had slides to look at, and their own notes, where "voting rights" was the only answer said.

[artalot]

I almost always give some sort of partial credit on essay tests. That said, I rarely ask questions where there is only one correct answer, so I think it's probably easier. If the question you're citing is like a multiple choice question (only one right answer, and all you are looking for is a factual answer), maybe it doesn't need to be an essay.

[the_geneticist]

Depending on the class/assignment, I'd either just give a comment for the incorrect part with full credit or give partial credit. 
And that's why I'd only use multiple choice for definitions.  I'd save free response for "give an example and explain" or other more complicated answers that have many possible correct responses.

[fosca]

When I gave my students short-answer tests, I emphasized the "short answer" and told them to just write down the correct answer(s), not to write down everything they know about the topic in the hope that the correct answer was there somewhere, and that they would lost points for incorrect information.  It was rarely a problem, because I only used short-answer for make-up tests and students would regularly not be able to answer anything (101-level gen ed normally given multiple choice).