I have supervised a lot of PhD students over the last 25 years and currently supervise a group of 15 PhD students at the University of Leeds in the UK.

I like one of the other answers that starts by saying that intelligence is neither necessary nor sufficient to obtain a PhD. Broadly speaking I agree with this. But there is a minimal level of intelligence that is required.

I know that intelligence is hard to define and even harder to measure but I have experienced a small number of PhD students who don’t seem to have the ability to understand (or maintain an understanding of) difficult concepts over a period of time. With these students, we go around in circles explaining the same ideas over and over again with little change in observed behaviour.

Some of those students have found it really hard to complete their PhD. But the level of intelligence required to obtain a PhD is not as high as one might think. And I think there are other factors that are more important in practice given that the student has that minimal level of intellectual ability required.

So let’s put intellectual ability aside and look at what else affects success assuming a student has that necessary intellectual ability. Here is my list of factors with the most important first.

Good Mental Health

I increasingly see students these days (PhD students I supervise, PhD students and Masters students I observe) who have poor mental health.

It is, perhaps, the single most important factor that can make students struggle to succeed in their studies.

When I was young and doing my PhD in the 80s I wasn’t aware of any poor mental health. Maybe I was looking in the wrong places. But I think it is more likely that things have changed, that life is a lot more stressful these days for many reasons, and that the prevalence of mental health problems has increased.

In my opinion, many universities need to increase the support that they offer in this important area.

[Of course, physical health is also important, and serious physical health problems can be really debilitating.]

GRIT

You can find lots about GRIT on the internet. In fact, it was one of my PhD students who introduced me to this idea.

GRIT is passion and perseverance for long-term and meaningful goals. Successful PhD students don’t give up. They may go through bad patches like everyone else but they have the internal resources (and perhaps the external support) to come through and keep going. They are determined and resilient.

Confidence / Resilience

Arguably this is part of GRIT. But I list it separately because it is so important.

Everyone experiences setbacks and rejections.

Some of you might have seen the professor who publicly listed all his failures (jobs he didn’t get, papers that were rejected) rather than his successes.

I have a long list of failures myself. There is a famous story of the guy who founded KFC who approached quite many banks for financial support for his fried-chicken business before finally getting a “yes”.

Whether it is true or not, I like the idea of someone who keeps presenting their ideas and keeps getting rejected but each time they present they have the same confidence as on day one. I have a mug with the caption – “success is the ability to go from one failure to the next without loss of enthusiasm”.

You need a lot of resilience to do this which is why I list it in addition to GRIT.

Curiosity

This is my favourite attribute that I look for in PhD students and, even more so, in post-docs.

Curiosity means they always want to know more and they want to know why.

This drives them on to dig deep, for example, into their data and see things that perhaps even I cannot see. It drives them to learn new skills and constantly move forward.

I like to give the analogy of surfing (not that I can do that in real life) and always staying on the wave as technology and ideas move forward.

Curiosity also extends to asking questions about your own results and could be a factor in helping a student to change tack because sometimes that is the right thing to do.

Emotional Intelligence

Emotional intelligence helps to ensure a good relationship with your peers and with your supervisor. I have known students who become derailed because of stuff going on with their interpersonal relationships.

Work Ethic

Of course, there are times when you have to work really really hard. But it’s not 24/7. Quality is more important than quantity and it’s not how many hours you spend but what you do in those hours. But, at times, some very hard work is required. How much tends to vary with the stage of the PhD (obviously it is very intense during the writing phase).

Honesty

Honesty is important. Students need to be open when they don’t understand something and not hide this. They need to be honest with themselves too.

Stephen Westland is a Professor at the University of Leeds (2003–present) and can be reached via S.Westland@leeds.ac.uk