A criterion is fallen if in the previous iteration of benchmarking its score was higher. Hence in Pick&Mix one might talk of a "fallen 2".
Note that benchmarking should not be viewed as a process which takes place once and once only. Rather, there should be re-benchmarking from time to time, not necessarily annually, but at regular intervals - for example, timed to coincide with the start of the review process for a learning and teaching strategy. Thus each criterion or indicator score has a path through time. Indeed, several of the constituent indicators of a criterion are likely to be scored annually as part of other processes such as IT planning or student support.
For more see trajectory.