thank you :-). The GASP is great and but i was wondering if you have used it yourself, and particularly only the NBE part? and if you have or someone you know has, how did that turn out?

I think much hinges on what sort of guilt you're thinking of. For example, you could be hypothesizing that anticipatory guilt (i.e., "I'll feel terrible if I hurt someone") would act to inhibit bullying. Or that some people who are plagued with guilt might engage in bullying as a way of venting their negative affect/inflicting pain on others to compensate for the pain they feel. (Actually, in that case I'd lean more toward shame than guilt as a factor.) Or that some victims of bullying feel guilty over having been "punked out," so to speak. And these are such different constructs that your choice of guilt scale would be different in each case. 

That said, I agree that the GASP is one possibility. I'd advise administering the whole thing (it's only 16 items, and you can't be sure the shame ones won't turn out to be relevant). Here is another: The Brief Shame and Guilt Questionnaire for Children (just 12 items!). 

Thank you Stephen. Your answer is actually what i have been trying to separate in my project. I am more interested in the guilt part because as you said it can be used to inhibit bullying behaviour. Thank you!!

Hello Guise! I'am currently working on my thesis with my partner.It's very difficult for us to look for a guilt questionnaires. I would like to ask if you can also suggest any questionnaires about guilt and our respondents were actually inmates. Thank You!

Hi i wouldn't be able to advise you about guilt and previous inmates but i found the GASP scale most helpful. The developers have a short one as well. It breaks down into sub-scales which might be of better use if you are looking into particular aspects of guilt, such as shame.