Doctoral Research Positioning and Originality

What counts as an original contribution to knowledge in a PhD?

It varies by discipline and institution, but it is always an addition to what is known rather than an amount of work done. Common accepted forms include new empirical evidence, a new method or instrument, new theory, an established theory tested in a context where there was reason to expect it to behave differently, a synthesis that reorganises a literature, a replication of a result that needed independent verification, and the transfer of a method from one field to another. Check your institution's own regulations, which usually contain the sentence the examiner is formally applying.

How do I know if my research has already been done?

Run a search designed to find the study that would make your work unnecessary, rather than one designed to support your claim. Search the vocabulary of adjacent fields as well as your own, search theses and dissertation repositories, preprints, conference proceedings and registered protocols, and trace citations both backwards and forwards from the closest studies. Then compare the closest five to ten studies against yours on question, population, setting, theory, design and conclusion.

How do I write a contribution statement?

In one sentence, name what is now known, the population or setting in which it holds, the evidence that establishes it, and what follows from it. Avoid verbs that describe activity or attitude ("explores", "investigates", "sheds light on", "contributes to our understanding of"), because they name no knowledge. Then test the sentence: could an expert say "we knew that", and does your design actually support the claim at the size stated?

My contribution has shrunk since my proposal. What do I do?

Re-derive it from what you actually have rather than defending the original size with weakening evidence. Then state in the thesis what changed and why. A smaller contribution defended completely is a stronger thesis than a large one defended partially, and examiners consistently reward the first.

Is a replication study enough for a doctorate?

In some disciplines yes, where the original result was consequential and contested and had not been independently verified. It has to be argued as a replication rather than disguised as something else, and the argument has to establish why this particular result needed repeating. Discipline conventions differ sharply, so calibrate against recently accepted theses in your own department.

Can I use AI to write my contribution statement?

This skill does not write passages for submission. It interrogates a statement you have written and returns the weaknesses in it. Any AI use must comply with your institution's policy and its declaration requirements, which vary by institution and by assessment, and where AI assistance is prohibited for a task the skill must not be used for it. There is also a practical reason: a contribution sentence you did not write yourself is one you cannot defend in a viva.