The phrase “significant, original contribution” is probably the best combination of words that we have to describe the something that a PhD candidate needs in their thesis to demonstrate that they are a good researcher and that they have done good work.
It’s also a worrying concept to grapple with for many candidates.
A “significant, original contribution” sounds like a singular result. It sounds like one fantastical theory, a number, a paragraph that shares knowledge with incredible impact.
Many candidates imagine something like this and worry because they don’t have one contribution, they have lots of little things. They have a collection of papers. They have a collection of projects (that was my thesis). They have many small results presented in one thesis, but perhaps no unifying conclusion.
Of course, as the title for this post suggests, these all add up to make a contribution.
The chapters, sections, results, papers, ideas, developments, conclusions – all together these make the contribution. “Significant” is a worrying word to candidates in my experience, because they try to imagine the number that goes with that. How many pages? How many papers? How big a bibliography? How much of the thing that I do?
This sum doesn’t have a number for an answer. Taking all the parts together, you have to judge for yourself: is this enough?
Ask your friends and colleagues: is this enough? Ask your supervisors: is this enough?
Is this enough?
Once you feel sure for yourself then you can move past a “significant, original contribution”. The sum of everything you present, everything you’ve done, all shows a real contribution to knowledge – and it shows a capable person who has created that contribution.