I had an interesting discussion with a colleague from Chemistry at a party last night. The discussion related to how many PhD students we would each typically have. In my case, I’ve never had more than 2 at any one time. This person typically took on 2 every year, while other Chemists in her Department could have 15 – 20 (or maybe even more) at any one time.
The issue I have is how one can properly supervise so many PhD students. Certainly, I think I would find it very difficult to effectively supervise more than 2 at any time. If you run a lab with lots of equipment, it may well be easier to supervise more than 2 at a time. Presumably if you have 20 or so PhD students, you must also have a reasonable number of postdoctoral researchers and research technicians and a reasonably large lab. You could then have a hierarchy where your postdocs essentially look after your PhD students, so you don’t need to meet will all of them every week.
This would certainly work in terms of ensuring that they are kept busy and that someone is available to help with any problems. My concern is that this suggests – to me at least – that these students are essentially being used as lab rats, rather than doing something that would be regarded as original and semi-independent research. I have heard some express the view that this doesn’t really matter as a large fraction of these PhD students will not follow an academic career anyway, and so they will still be learning useful skills that they can take out into industry. I just don’t feel that that is acceptable. A PhD is meant to give people the skills, knowledge and ability to follow an academic career even if they choose not to do so.
I must admit that I don’t really know much about how PhDs are supervised in other areas of science. It may well be that those who have 20 or more PhD students are perfectly capable of managing and supporting these students properly. These students may also graduate with a degree that is valued throughout the world in academia and in industry. I would also be happy to have comments from those who are more familiar with these kind of environments.