At my university in the UK, candidates doing a full time PhD (3 years) have to submit a 1st year report which includes literature review, the "gaps" that will be tackled by the doctoral work, expected outcomes, research methodology, Gantt diagram of the future work, the completed training plan, and some preliminary experiments (if any).
The supervisor makes a report about the performance of the candidate (training, attendance to meetings, etc.).
A committee of faculty members (excluding the supervisor) reads the candidate report and the supervisor report, and examines the student on the content of the report and challenges the topic, etc. It's like a mini-viva. The committee is called to make a decision if the candidate is able to complete the PhD in the next 2 years or not. If the answer is not, then the candidate gets another chance in 2 months and if they fail again, need to leave the program.
My question: How can one make a decision about the ability of a candidate to complete a PhD from their performance in the first year? I have seen people struggle in the first year and then do amazing work and vice-versa. Questions like "the ability of the candidate to perform novel work" cannot be answered after the first year.
I am early-career faculty.