One of the best ways currently available to check that the Level 3 filtering is working correctly is the statistics that are visible under "L3 Filter" of the daq_monitor display. For each filter script and each filter within that script, numbers of calls and passes are recorded.
It has to be admitted that there is a somewhat bewildering amount of information displayed. We are thinking about how to monitor this information automatically. However, by checking rejection factors for a few typical L3 scripts you can help test whether or not the L3 filtering is working correctly.
| L3 Script Name | Expected Rejection Factor |
| EM_HI_2EM5_SH | 40 |
| EM_HI_SH | 25 |
| EM_HI_TR | 60 |
| JT_65TT | 55 |
| MU_A_L2L3L0 | 1.5 |
It is an important duty of the DAQ shifter to ensure that this information is being updated correctly. If not, then it is likely that the L3 Filter Server process that produces the information has died and it should be restarted according to these instructions.