Hi @ OnTheBenchOfDoom ! These are three criteria for selection by a Cambridge college:
- intellectual and academic potential in the subject;
- suitability for the particular Cambridge course, including workload, intensity, supervision-based teaching;
- being in the best few available to the college.
Suitability for a particular college does not come in to it. I work with schools and my colleagues and we have never heard a College Admissions Tutor or subject Director of Studies mention this.
Another thing to note is that most strong candidates are difficult to separate on the both the draft offer/pool list and the final pre-offer ranking list. In each case, the decision is then intuitive, involves guesswork, is subjective and may be arbitrary. And some of the decision makers acknowledge that they sometimes get it wrong.
For example, for October 2017 entry, my daughter was winter pooled. She went on to take a Double First, is now on her MPhil course at Cambridge and making PhD applications. The ‘rejecting’ senior interviewer and DoS had the grace to say he just got it wrong, as she finished ahead of each of his preferred candidates in each year’s exams. His original reason? She was strong but the others had a bit more subject knowledge and he had to make a decision somehow. (Nevertheless, his summary notes on her application were highly complimentary, according to two other colleges’ DoS. All three colleges are completely different in so many ways, yet they were all interested in her.)