### Giving negative grade for wrong answers in multiple choice

Number of replies: 14I want to know if it is possible to give a negative grade to wrong answered multiple choice questions. What I want to do is the following:

10 multiple choice questions, each one with an unique right answer

Each right answer means +1

Each wrong answer means -0.33

Each unanswered question means 0

For example, 7 right answers, 2 wrong answers and 1 question without answer would be 6.33.

I see that I can give a negative qualification to wrong answers, but once the quizz is done, each question has a qualification between 0 and the top, even if the answer had a negative qualification.

The kind of questions I am using are single answer multiple choice. I also tried multiple answers. In that case, if they choose the right answer (+100%) and a wrong answer (-33%) they obtain 0.67 in that question, but if the only aswer is wrong (-33%) they obtain 0 in that question, so the problem is the same.

Any comment/help?

Thanks in advance.

### Re: Giving negative grade for wrong answers in multiple choice

Hi Angel,

that´s an interesting topic, especially when switching from paper to electronic tests.

[giving negative grades for questions]

To be honest, we simply don´t do it because the worst result for a test is "zero". As a consequence: If the worst possible quiz result is zero, negative questions grades don´t make sense.

[partial credits]

We don´t give partial credits, because this ends up in endless discussions with students about how to value a correct or a wrong answer. In your example: Why is one correct answer = +100%, whereas one wrong answer is -33%? Or: if you have three wrongs answers, one of those is -33%, where in another question you may have two wrong answers, so any of those is -50% ?!?!?!

If you switch from paper to "e", the first question from students and teachers is always how to give credits to "ungiven incorrect answers", because this system is often used on paper (example: five answers: three correct, two incorrect; each answer = 0.2 credits, correct if checked, uncorrect if unchecked). But this seems to be inpossible in electronic systems?

We simply use multiple choice with four options and only one is completely correct and gives +100%. The other three are incorrect or at least partially incorrect and give 0%. We give differentiated feedback for any answer. Since we use this we don´t have any discussion about partial credits.

Cheers, Marcus

### Re: Giving negative grade for wrong answers in multiple choice

One example I can think of for Angel's request is a driving-license exam: correct answers worth 1, but wrong answers vary in their amount of negative impact depending on whether they err on the side of caution or err on the side of recklessness. It is, I think, a good way of addressing the fact that "not all wrong answers are equally wrong" or, put another way, "it matters how you were wrong."

### Re: Giving negative grade for wrong answers in multiple choice

This would make it similar to the SAT test:

Correct = 100%

Don't Answer = 25%

Wrong = 0%

You might need to tweak the numbers a little bit, and I'm not sure this will do quite what you want, but I think with these numbers, random guessing should balance out at the 25% mark for a grade, which seems to be your goal (though you were aiming at 0% for random guesses).

Does this work for you?

### Re: Giving negative grade for wrong answers in multiple choice

### Re: Giving negative grade for wrong answers in multiple choice

10 multiple choice questions, each one with an unique right answer

Each right answer means +10 (100% for a 10 point question)

Each wrong answer means +1 (10% for a 10 point question)

Each unanswered question means 0

The actual quiz grade item should be hidden and there should be a mirror grade item which takes the score of the quiz and pass it to a formula such as

=(||quiz||-mod(||quiz||,10)-(mod(||quiz||,10)*3.3))/10

So with your example of 7 right answers, 2 wrong answers and 1 question without answer the quiz score will be 72 but the calculated score will be:

(72-2-(2*3.3))/10=63.4/10=6.34

In the case of 3 right answers, 5 wrong answers and 2 question without answer the quiz score will be 35 but the calculated score will be:

(35-5-(5*3.3))/10=13.5/10=1.35

Some further fine-tuning may allow this approach to work also for the extreme case of all wrong answers.

### Re: Giving negative grade for wrong answers in multiple choice

>10 multiple choice questions, each one with an unique right answer

>Each right answer means +10 (100% for a 10 point question)

>Each wrong answer means +1 (10% for a 10 point question)

>Each unanswered question means 0

>

>The actual quiz grade item should be hidden and there should be a mirror grade >item which takes the score of the quiz and pass it to a formula such as

>

>=(||quiz||-mod(||quiz||,10)-(mod(||quiz||,10)*3.3))/10

This approach could also work for longer quizzes. If you have less than 10 questions, use the numbers as given. If you have between 10 and 99, change all the 10s to 100s, and give only 1% for a wrong answer. (Will moodle allow 1%?) If you have between 100 and 999, make the question worth 1000, but then you have to give .1% for wrong answers and I'm sure moodle wouldn't allow that!

### Re: Giving negative grade for wrong answers in multiple choice

### Re: Giving negative grade for wrong answers in multiple choice

Thanks again,

Angel

### Re: Giving negative grade for wrong answers in multiple choice

When I have finished my current re-write of the Moodle question engine, then it will be possible. Indeed, that bit of the new code already works find. I just need to finish the rest of it, and get it into a Moodle release.

### Re: Giving negative grade for wrong answers in multiple choice

### Re: Giving negative grade for wrong answers in multiple choice

Hello Tim,

I'm having the same problem and I wonder when will it be finished..

Thank you so much.

### Re: Giving negative grade for wrong answers in multiple choice

The aim is to get it into Moodle 2.1. Most of the code is finished. I need to complete the missing pieces, and it needs to be reviewed by the Moodle HQ folks before it is included.

### Re: Giving negative grade for wrong answers in multiple choice

Some older posts about it:

http://moodle.org/mod/forum/discuss.php?d=47599

Code change summarized here:

http://moodle.org/mod/forum/discuss.php?d=85473

Cheers,

susana