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Supervisor diss feedback directly contradicts advice I received from module leader.

For my dissertation, I looked at the effects of artificial sweeteners on glucose levels. This involved getting participants to drink tea/coffee and have their glucose measured. Each participant took part in two trials - a sugar trial, then a sweetener trial. I took 7 glucose readings per trial per participant over the course of an hour (fasting glucose reading, then 6 readings every 10 minutes following consumption of their drink). I would then compare the sugar glucose to sweetener glucose to see if sweeteners elicited a glucose response. I also collected demographic data from all my participants including age, gender, height, weight (for BMI calculation), exercise levels and whether or not they frequently consumed sweeteners. My reason for collecting all this data was to see if there was any correlation between these demographics and glucose response. I.e, did BMI/age/gender etc effect glucose response in any way.

Now my supervisor for my dissertation only just started working at my uni this January and she told me she knew nothing about stats (she's a microbiologist, apparently you don't need stats for that so she apparently never learnt anything about them) and referred me to the dissertation module leader for any help I needed with them since she's the go-to stats person and took us for our stats lectures in year 2.

So once I'd collected all my data, I saw the module leader as instructed for advice on how to analyse my results. Firstly, the module leader told me that I couldn't do any testing with my demographical data. She told me to just disregard it all. I tried asking if I could do anything at all with it since it seemed a shame not to try and incorporate it, but she said no because it wouldn't show anything of significance since my participant number (34; I really struggled to get that many so it wasn't lack of effort) was too small a sample size to derive anything conclusive from it. Fair enough, made sense as some of my categories would have only had, for example, 2 people in them and obviously you can't test for significance with only 2 people. She then told me to do a paired T test on my sugar data, then on my sweetener data and compare the two, and also told me that instead of looking at individual sugar v sweetener response, to instead find the average of each time point over all participants and do a paired t test on the averaged readings per trial time point, not on each individual reading. Again, that made sense since I was looking for an overall effect since every one has a different metabolism so individual analysis wouldn't be likely to show any real results, it would just show that one person's particular reaction, not if sweeteners elicited a glucose response in general. So again, what the module leader advised made sense so I did my testing as she told me to.

I've just received my diss mark and feedback today. I got 63 which is decent so I'm fairly happy, but my feedback told me my results section was poor and the reasons why directly contradict the advice I was given. It was my supervisor who marked my diss and she said I should have used a 'more appropriate' test than a t test - but that's what I was told to do - and that I should have tested my demographics BECAUSE of my small sample size - again, I was told NOT to test them because I didn't have enough for significance. The rest of my feedback was small things like forgotten italics once so I really feel the majority of the marks I lost were in my results and I want to know why.

Am I wrong to feel a bit cheated here? I'm not angry at my supervisor but I feel like either I was given really bad advice by the module leader which directly impacted my grade (I appreciate we're supposed to learn independently but the point of supervisors/lecturers is to guide you and give you good, reliable advice when you're struggling), or my supervisor doesn't understand stats enough and has marked me down wrongly - but this seems unlikely as it has been second marked and surely any mistakes by my supervisor would have been noted and corrected?

Should I bring this up? I'm not even challenging my grade, but I want to know why there appears to be such a contradiction in the advice I was given vs the feedback I got as it does seem like I lost marks for my results.

(edited 8 years ago)

Reply 1

alleycat393

Hmm this is a tricky one. Do you have a personal tutor to talk to? You cannot really appeal the mark (i.e scientific judgement) but you may have grounds for appeal based on supervision. From what you've described I have a feeling that it's just a question of one person preferring to look at the data one way and another preferring another way. And since your supervisor was marking the dissertation she should have advised you about stats. Ideally you should have sat down with someone, played around with the data with their guidance, come up with the best way of presenting and analysing it to answer your research question and justified this in your dissertation. One or more parts of this process was either missed or not followed properly and hence the feedback.

Reply 2

Rae18

Thanks for your reply.

We don't have personal tutors in year 3. I'm not interested in appealing my mark, I'm just a bit frustrated that 1) I was given a supervisor who knows nothing about stats and 2) that my supervisor sent me to the module leader who gave me advice which I followed to a T, but is then critical saying I used all the wrong testing - but I ran my results past the mod. leader after I'd completed my analysis and she confirmed it was all appropriate and correct! I tried to get my supervisor to advise me on stats but every time she'd brush me off with "oooh, I know nothing about stats". I asked her if p = 0.05 is significant or not as I couldn't remember which way round it was and she said "I've got no idea. I don't know anything about stats" so yeah, my supervisor SHOULD have been the one to advise on stats but she either couldn't or wouldn't so this is why I'm so frustrated to be criticised when I had no choice to but seek advise from someone else and who she directed me to. I feel like my supervisor has marked my diss with a very biased mind and failed to consider that the advice I was given by the module leader may not be the advise she'd have given me. She's marked it very much with a "I'd have done this" mindset I think when she really shouldn't have given that she TOLD me to see someone else and refused to help me herself with stats. I don't think it was a case of having not included something or done something wrong because my feedback was purely about the type of tests I did and how I graphed them and about them being inappropriate tests not that my data was wrong. For example she said I should have used median but I was told by my mod. leader to use the mean. I was told by supervisor to 0 all my time point data (this was the only piece of advise she gave me and when I asked her to explain why I needed to do this she couldn't answer it), but mod. leader told me to average them. Feedback said I should have tested demographical data but mod. leader said there weren't large enough sample sizes to test them (which is correct as some of my categories only had 2 people. You need at LEAST 3 for significance testing). I also saw my department head about where to put some of my graphs and he told me to put them in the appendix and told me exactly which ones to put there. Supervisor's feedback said these graphs should have been in results. So yeah, there's contradictions all round.

"Ideally you should have sat down with someone, played around with the data with their guidance, come up with the best way of presenting and analysing it to answer your research question and justified this in your dissertation". This is what I did do when I saw the diss module leader/stats lecturer - that probably wasn't clear in my original post but she sat down with me, looked at all my data, asked me what I was testing and looking for etc and we discussed what I could do with it and played around with it in R and excel to find the best way to represent it, this is how we settled on what I eventually did in my diss. She spent a good hour at least helping me so it wasn't like it was a really quick "do this, go away" thing. We really thought about it and she decided on x, y, and z test which when explained to me made perfect sense for my data, and I put a lot of effort into my results all to be told "very poor section" and criticised for things I'd been told to do.

I agree that it seems like this is a matter of personal opinion on what test would have been most suitable, but again I feel like my supervisor isn't understanding that my results/analysis were done based on advise from the module leader who she told me to see, so she should have marked my diss with a more open mind, or at the least asked the mod. leader what she'd advised me to do so she could mark it with that in mind.

(edited 7 years ago)

Reply 3

alleycat393

I'm surprised that you don't have s personal tutor. Other people you can possibly contact are the module leader, the student office or the student union. But it doesn't sound like you want to do anything at this point though. I think the important lessons are to flag up supervision problems ASAP, write for and know your audience and justify why you're doing what you're doing. No one who does science can get away without knowing anything about stats and certainly not someone supervising students.

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Supervisor diss feedback directly contradicts advice I received from module leader.

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