I am close to quitting my PhD - my sup has given me a few days to work on a sampling strategy for a qualitative study - which is fine but I'm failing in my justifications - why I'm doing one thing and not another. It just feels to me that in qualitative research anything goes. How do I get better at defending myself and my methods? I just got deferred in my upgrade viva and now it feels like the end is in sight, that the only option left is to quit. Are there any 'happy quitters' out there?

From your post it seems that you are having a crisis of confidence, which I am not belittling. It is common to have set backs in research and defending your research, how you did and how you are interpreting it are not easy skills to acquire. They come with time. In terms of methodological development, there must be some literature in your subject area? Also even the most senior researchers in one area may not agree on how to collect data. If you have to choose between two different methods, ask yourself:
Which one is best for my type of sample?
Which one is best for the size of the sample you intend to work with?
What are the factors which differ from published papers you ahve read?
What are the basic gold standards? Are you proposing to modify any established method? If so, why?

Have you spoken to your supervisor about your concerns?

Deciding to quit your PhD is a very serious decision and It is also worth considering whether there are alternative solutions to your leaving. Could you take a short break or give it another chance for a set period of time?

If, as a last resort, you decide to leave, then do it without regrets and hold your head up high. Not everyone takes the brave decision to do research at such a high-level. What you have achieved is still amazing!

However difficult a PhD has been and whatever the outcome of it was, a period of research will have given you some amazing skills which are applicable to a wide range of careers and activities. You will have also learned an amazing amount about yourself which is an accomplishment in itself.

Best of luck,
Nathalie

I'd advise you to take a deep breath and go back to basics. I often bounce back to textbooks like "Research Methods and Statistics in Psychology" or whatever would be more apt for your subject. This outlines the key concepts and methods in research and gives references for further reading. Then once I had clarified that, I would look at examples of studies using these methods. Sometimes when panic strikes, it's hard to see the woods for the trees and it can be helpful to gain clarity and a clear overview by rebooting the who, why, where, what and when foundations for your research. I agree that it's really important to speak to your sup. Ultimately it is your decision and I wish you luck in whichever path you choose!

Dear Nathalie and Zipidee
Thanks so much for your contributions and comments. The reason why I think I was struggling so much is that my Mum had terminal breast cancer - I was main carer and she has since died (in October). I am due to return on 1st March so hopefully will be able to then. My supervisor is aware and I hope to be guided by your advice. If you took a break from your PhD and came back I would love to hear more from you.

Best wishes