It is important to understand the difference between positive and negative bid preferences when constructing your bids.

Negative Bids

        Prefer Off

        Avoid Pairings

Negative bids remove pairings from the available pairing pool, while positive bids take pairings from the available pool and add them to your block. 

Positive Bids

        Award Pairings

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.

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.

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 details, see Denial  Mode.