As I understand it, the raw score is the standard test score you’d receive in any test (usually as a percentage) and relates to just you. The percentile is how you fared in comparison to others taking the same test. So in an initial recruitment test, you may score 90% over all which alone, would be a pass, but if everybody else scored 98%, you’d be the lowest, so wouldn’t be progressed. They often grade results from A-D or whatever, but the principal is the same.
Most initial assessments you’re sent from TOCs for any role use percentile scoring as it’s an easy and effective way of sifting candidates.