A PhD - or at some UK universities a DPhil - is a Doctor of Philosophy higher degree. A PhD is awarded for completion of independent research that makes an original contribution to your chosen field. Because a PhD can be awarded in any research discipline and because almost all countries have a direct equivalent of a PhD (even if the name is different), a PhD is universally recognised concept. 

Requirements for completion of a PhD very between different disciplines, institutions, and countries. Typically, candidates are required to submit a written thesis and to then defend their research in a viva.

A typical full-time applied health research PhD in the UK takes three years. The PhD candidate must produce a body of research consisting of usually three or more distinct studies that are inter-related. At the end of the PhD the candidate should submit a written thesis (typically somewhere between 30,000 and 50,000 words).

The studies that make up the PhD can either be based on a single methodology (e.g. meta-analysis) or multiple different methodologies, as in a mixed methods PhD that combines both qualitative and quantitative methods. Often PhDs based around a single technique are more methodological, for example a PhD focussed on meta-analysis might attempt to develop novel analytical approaches for meta-analysis rather than simply performing three different meta-analyses.

The ideal PhD thesis tells a story with the completion of each study leading in to the next study. For example, the first chapter could be a systematic review to identify potential interventions to reduce postoperative pneumonia, the second chapter might a pre-trial health economic model to identify which of these interventions are potentially cost-effective, and the third chapter could be a small pilot clinical trial to inform the design of a definitive trial to evaluate these interventions.

• A PhD does not need to change the world! A PhD should represent "original" research that generates new knowledge - it is ok for this to be a small incremental increase in knowledge.

• A PhD does not need to be done alone! Although a PhD should represent "independent" research, in the era of 'team science' the reality is that you will work on your project within the support structure of a wider team, perhaps even including international collaborators. At the PhD viva you will be expected to clearly articulate what your personal contribution was - and this needs to be substantive, but no one expects you to have literally done everything underlying your research.

• A PhD is not a holiday! After some years in busy clinical training, many medical doctors like taking time away from the clinical training to undertake research. They can expect a different pace and much more flexibility; most PhD research fellows can set their own hours and pick when they take leave. However, at the end of the PhD it is entirely up to you to get your thesis written and submitted - no one will do this for you! Getting to the point of submission takes years of hard work.

In the past a debate topic for UK medical doctors was whether to undertake a PhD or a MD. In the UK, an MD (Doctor of Medicine) degree is a postgraduate research degree open to qualified medical doctors. It is typically reduced in duration (2 years versus 3) and scope (minimum 2 substantive results chapters versus 3) compared to a PhD. It should not be confused with either a PhD (it is a distinct degree) or MD degrees awarded in countries such as the USA where that is a primary medical qualification equivalent to MBChB / MBBS in the UK.

I think historically medical doctors were more likely to register for a PhD if their research was laboratory-based, whereas they might be more likely register for an MD if they were undertaking clinical (applied) research. MD registrants might have been perceived to be older, further in their clinical training, and more independent. In current practice, these distinctions are completely gone as PhDs are now awarded across the full scope of medical research.

Some people still have strong views, but ultimately, whether you choose to register for a PhD or MD is largely a personal choice. Your prospective supervisor may have a strong preference, perhaps if they are looking for a research fellow to work on a project for three years. Some funders will only fund fellowships for PhDs.

Some UK universities offer a PhD by publication route. This generally involves putting together in to a thesis three or more good quality peer-reviewed journal articles on a single theme. You will usually add to this some additional text as an overarching introduction and discussion. After you have submitted this as a thesis, you will then have a viva.

A PhD by publication can avoid the time (and expense) of taking three years out for dedicated research. I think this can be a good option for people who have been working as (non-clinical) research fellows for some years who are looking to be recognised for their expertise. But for early careers doctors I think a PhD by publication misses the point! Although ultimately a PhD can be reduced to just another tick box requirement, the PhD journey in itself has huge value in developing both technical research skills and maturing you as a rounded researcher.

Take a look at my pages about when to do your PhD and how to find and fund your PhD.

If you are interested in exploring PhD opportunities at the Global Surgery Unit, please get in touch.