In Pick&Mix, a criterion is falling if in the next iteration of benchmarking its score is likely to be lower. Hence one might talk of a "falling 5".
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.
Sometimes it is clearer to use the phrase "and falling" after the criterion score - e.g. to say "3 and falling" rather than "falling 3" - especially on bad phone lines where "fallen" sounds similar to "falling".