Greetings,

 June PBS Awards - What is SLG?

Some people have noticed 'Awarded by SLG' on their June bid awards.  Secondary
Line Generation (SLG) is the final process that PBS performs in an exhaustive
search to find you a complete block.

If Denial mode has removed all deniable bid preferences and still cannot
produce a complete block, the program tries to create a block using only the
Award bid preferences.

If the program still can’t create a block, it makes a final attempt using only
the system-generated Award pairings bid preference. This final attempt, called
secondary line generation (SLG), ignores all preferences and performs an
exhaustive search to find you a complete block.

If you don’t have any deniable bid preferences, Denial mode goes directly to
the final completion attempt and attempts to build your line using SLG rather
than assigning you a reserve line.

After researching lines impacted by SLG, we can see those lines were also
impacted by the Unstacking process.   For the more junior lineholders, pretty
much all that was left were trips on the weekends. Often these trips have a
lower average daily TFP value.  For example, in SEA there were many four day
trips worth around 17tfp.  Four of these trips, one on every weekend, would not
make a legal line.  That would come to 68tfp and the lines for SEA in June had
to be at least 70tfp (SEA Line average = 80TFP).  The program tried different
strategies - maybe one of the multiday trips had to be removed and turns had to
be used...but there were very few turns left to assign.  Or, turns were tacked
on to the beginning or end of a four day trip in many cases.  Again, the
majority of these trips are all being assigned by 'unstacking'.

We hope this helps in explaining SLG.   If you have any questions, feel free to
post them in the Class Bid Q&A conference.

Your Joint PBS Committee