Is a student with weak written examination skills also a weak candidate for PhD? A friend of mine is enrolled as a master's student in Computer Science and considering to convert to a PhD at the same university. My guide acknowledges that he has excellent interpretation, understanding and deduction skills. He is also very good in implementing ideas as code.

He has been able to score just around average grades in all the subjects primarily owing to class projects. The problem he attributes to is that he is not at all good at reproducing things during the examination. In fact, while studying, he tends to ignore all the information like names of techniques, methods etc and just focus on what and how things work. In fact, he doesn't like to write the exam at all and usually just focus on the most tempting or the most thought provoking questions in the paper. (and just writes something to other questions for the sake of writing).

Now, he is just falling short(by 0.2) of the CGPA criteria set at our university to convert to a PhD. So, not being able to properly write examinations and not being able to score good grades, makes him a weak potential candidate for a PhD or does it affects his chances of successfully completing a PhD ?
Let's map what you've written about your friend, onto the sort of things we might look for in a promising PhD candidate, to see why, although exams and PhD research are very different beasts, we might learn about one thing from another.


Meticulous? No.
Demonstrates good grasp of the substance and relevance of theory? No.
Can perform under pressure? No.
Can follow protocols? No.


As you can see, although you say the grade point average is only just below what is needed to convert to a PhD, there are a few warning signs that this student might not be appropriate PhD material; both the student and the decision-making body should pay heed.

I appreciate that this may not be easy for you to hear, as they are your friend. But really, PhDs aren't for everybody: there are lots of domain experts who are not PhD candidates; and there wil be lots of successful Computer Science PhDs who will never be such good programmers as your friend. A PhD is a measure of academic research skills, not of industrial skills or life skills.

Computer science and software engineering are two different disciplines, though they are related. Different institutions will teach them with varying degrees of overlap. But they are distinct. Maybe your friend is a talented software engineer who needs to specialise there, rather than in computer science.