It is important to understand the difference between positive and negative bid preferences when constructing your bids.
Negative Bids
Prefer Off
Avoid Pairings
Note: Negative bids remove pairings from the available pairing pool, while positive bids take pairings from the available pool and add them to your block. With negative bids only one instance of the bid preference within the pairing must match the bid preferences.
Positive Bids
Award Pairings
Note: Remember that the junior buddy’s bid is used to build the block for both buddies, but the senior buddy should also enter a bid, as a precaution. With positive bids the N-PBS Scheduler looks for pairing attributes that match the bid preference, only one attribute of a pairing must match a bid preference for it to remain in the available pairing pool.
Consider the following example:
Start Pairings
Prefer Off Monday, Tuesday
Avoid Pairings IF Departing On Between 01:00 and 06:00
Award Pairings IF Layovers in MIA, BOS
Award Pairings
In this example, the N-PBS Scheduler reads the Prefer Off and Avoid Pairings preferences and immediately removes all pairings that work on Mondays and Tuesdays and all pairings reporting between 1:00 am and 6:00 am. The Scheduler then begins to look for pairings in the available pairing pool that contain at least one layover in Miami and/or Boston. You will not be awarded a pairing with layovers in Miami or Boston if it works on a Monday or Tuesday or departs between 1:00 am and 6:00 am.
All pairings that operate on a Monday or Tuesday are removed from the available pairing pool by Bid 2. All pairings that depart between 1:00 am and 6:00 am are removed from the available pairing pool by Bid 3.
Note: If the N-PBS Scheduler enters denial mode Set Condition, Prefer Off, and Avoid Pairing bid preferences are removed from your bid and your bid is reprocessed. For further information, refer to the Denial Mode article.