If shuffling does not produce a complete block, the N-PBS Scheduler enters Denial Mode. In Denial Mode, the N-PBS Scheduler removes your (Set Condition, Prefer Off and Avoid Pairings) bid preferences.
When denial mode is needed, the N-PBS reads the 1st bid preference in the bid group and tries to build a line that honors this preference, along with any Award Preferences entered. It then reads the 2nd bid preference (in the bid group) and tries to build a line that honors this preference in addition to any preferences Set Condition, Prefer Off, and Avoid Pairings already honored. For example, if the first preference was honored, the system will now try to honor the first and second preferences together, but if the first preference was denied, the system will now try to honor the second preference on its own with any Award Preferences entered.
The N-PBS Scheduler goes through your entire bid this way. By continuing to add bids from the top down in this way, the N-PBS Scheduler will find the best possible line given the bids in this bid group.
Denial Mode handles certain deniable bid preferences differently:
Set Condition and Avoid Pairings bid preferences are not used at all, even if you have more than one option on the bid preference, such as Landings in SEA or SFO.
Prefer Off bid preference options are removed one at a time if you have more than one option on the bid preference, such as a list of preferred days off. In this case, Denial Mode removes the date at the end of the list first and works towards the left if it needs to delete additional days or dates.
The N-PBS Scheduler tries to award pairings to reach the Threshold Value for a given Credit Window. However, as long as your block is above the Minimum Value, the N-PBS Scheduler does not go into Denial Mode to force your block above the Threshold Value.
Note: The N-PBS Scheduler will abandon the current bid group and move to the next bid group if a bid preference with an Else Start Next Bid Group or Clear Schedule and Start Next Bid Group cannot be honored.
Bid Groups are independent of each other. Bid Preferences are only relevant for the bid group they are contained in. The N-PBS Scheduler clears anything (Pairings or Reserve Days) and begins processing the next bid group.
Note: Administrators set the Minimum, Threshold and Maximum Values for Minimum, Normal and Maximum Credit Windows.
If you request a Minimum credit block (Set Condition Minimum Credit) or a Maximum credit block (Set Condition Maximum Credit), the N-PBS Scheduler WILL go into Denial Mode if the block is not above the Minimum Value, even though the block may be within the Normal Credit Window.
If Denial Mode cannot honor the Set Condition Minimum/Maximum Credit bid, the next completion attempt reverts to the Normal Credit Window.