WHAT IS A PREFERENTIAL BIDDING SYSTEM?
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Intro
This site was designed by Advanced Optimization Systems to be a resource for those wishing to learn more about preferential bidding systems in general, as well as specifics about our PBS implementation. For the best learning experience, we recommend reading all pages available in our navigation bar starting from left to right, but feel free to skip around. We welcome crewmembers and planners to take advantage of this guide and we sincerely hope that we can help you in your quest to answer:
What is PBS?
A PBS is a Preferential Bidding System for allocating bid month pairings to crewmembers based on individual crewmember preferences. The result is a line that is specifically built for each crewmember.
For crewmembers, this means that they can build their own lines. They can submit their individual preferences for off days, pairings, attributes and characteristics that will be considered when the system constructs their line. These requests, along with pre-assignments (vacation, training, medical and military leave, carry-in pairings, etc.), are factored in with their seniority to build the best line. This gives crewmembers, even junior ones, the best chance at getting a line they desire. Preferential Bidding Systems are a tool to make sure lines are created and assigned fairly and efficiently.
For companies, Preferential Bidding Systems creates a line solution in one process without the need for pre-built bid lines followed by a post-award trading phase. It also eliminates the costs associated with conflicts between pre-built bid lines and carry-in/pre-assigned activities. Consequently, fewer reserve crewmembers are needed, especially at the beginning of the bid month. Furthermore, the simpler process allows crew planners extra time to handle last minute schedule changes.
Clearly, a PBS solution can greatly benefit both the crewmember and the company if implemented correctly. It improves crewmember convenience while reducing costs for the company and definitely deserves consideration for any airline.
Bidding
In general, PBS offers following bidding options:
Off days: Bid to have certain dates off. It is the easiest and most popular bid.
Pairings: Bid for a specific pairing. It could be by pairing ID, or pairing IDs on specific dates or weekdays.
Pairing Properties: Bids for certain pairing attributes, such as report time between, release time between, connection duration, layover duration, layover cities, length of pairings, commutable pairings, standup pairings (CDO, Continuous Duty Overnight), sub-equipment type, average credit, deadhead preference, landing cities, and number of landings per duty, different base, etc.
Line Characteristics: Bids for certain line characteristics, such as average line credit, maximum days off, commutable work block, cadence, trip mix types, and work block size, off-day between work blocks, etc.
On Date General Bids: Bids for specific dates, such as report time between on specific date, release time between on specific dates, pairing length on specific dates and layover city on specific dates.
Fly Avoid or Fly With: Bids to fly avoid ( such as check airman or a specific crewmember) or fly with specific crewmember.
Position: The position preference is for flight attendants such as service director, or different language positions.
Reserve: Bid preferred reserve off-days/properties or pre-built reserve hard lines and to bid as line holder or reserve alternatively. Or bid reserve duty dates in a combo line, a line contains both bid month pairings and reserve duties.
Pre-Built: Bid pre-built hard lines (such as true CDO lines).
In addition, most systems offer "Standing Bids". These are a collection of each crewmembers' personal preferences. If a crewmember ever forgets to make a bid for a month, the system will use his/her Standing Bids to award line.
Most PBS vendors offer variations on these options. Where they differ is the methodology in which they process these requests.
Methodologies
Most preferential bidding systems allow crewmembers to rank the preferences they list with their bids. How each individual system deals with these rankings and preferences is known as their bidding methodology. A few common ones are listed below.
[Weighted/Pointed Preferences] (Value-Weighted List)
This method asks crewmembers to assign different points to the preferences/pairings. Of all possible leagl lines at your seniority, the one with the most points will be awarded. With this method, it is difficult for crewmembers to accurately describe their preferences since the line with the most points is not necessarily the ideal line. It also gives crewmembers the added burden of calculating the number of points they should assign to certain preferences or pairings. Furthermore, it is also impossible to describe certain preferences using this method such as using the "AND" operator with two different preferences.
[Prioritized Preferences] (Rank-Ordered List)
This method asks crewmembers to prioritize their preferences by arranging the bids in a sequence. The "AND", "OR", "IF" logics may be assigned between the bids. Crewmembers may also bid commands such as "award", "ignore", or "restart" among them. However, lines are built without knowing what is really going on or even if it is legal. If no legal line is built after going through all the bids, crewmembers may ask the system to ignore their preferences in reverse order. Preferences may be put in multiple sets or groups. If the current set cannot be awarded with a legal line, the next set will be used. There is no relationship between the sets. The next set is simply a backup if the previous set fails.
[Accumulated and Prioritized Layers/Pools]
This method records preferences in layers/pools. PBS will try to award a legal line based on the pairings that meet all the preferences (with AND/OR logic) in the first layer. If no legal line is awarded, PBS adds the pairings in the next layer and tries to award again, and so on. In this way, the most preferred pairings will be held and awarded while adding the other less preferred pairings to finish a legal line. Crewmembers can also bid to discard existing pairing pools so there is no accumulation. This method is the easiest and the most comprehensive. It is also possible to view the exact pairings qualified in each layer immediately, so each crewmember can predict his/her chance in the layer being awarded, which also helps crewmembers submit preferences correctly.
Goals
Legal Lines
All awarded lines must not conflict with carry-in and pre-defined activities while conforming to all government and company/union requirements.
Honor Preferences by Seniority
PBS must respect seniority. It is essential that a preferred and legal pairing not be awarded to a more junior crewmember if it is available to a more senior one.
Acceptable Results
PBS should minimize open pairings (ideally none), to minimize the number of reserves required. To deal with this, PBS must be capable of dealing with situations where crewmember preferences need to be ignored for the sake of company goals.
High Overall Satisfaction
Overall satisfaction is the key. Any PBS can satisfy senior crewmembers, but satisfaction among junior crewmembers is what separates different PBS.
Acceptable Running Time
A PBS should finish and publish the results of all bid pacakges in a reasonable amount of time.
Algorithms
In order to accurately understand Preferential Bidding Systems, it is essential that you familiarize yourself with some different core algorithms
Greedy
A greedy algorithm is one that uses a "First Come First Serve" concept. Lines are awarded starting with the most senior. If a line is legal and available, it is awarded. A greedy algorithm does not consider the preferences of junior crewmembers and offers the least overall satisfaction. It cannot deal with open time since uncovered pairings might be on any date requiring the need for more reserves.
Back Tracking
A back tracking algorithm is similar to a greedy algorithm. It awards lines based on seniority starting with the most senior. However, if the algorithm sees that a pairing that satisfies a junior crewmembers preferences, but has already been awarded, it can go back and swap or find another pairing to the senior crewmembers pairings so that he/she is still satisfied, while awarding the pairing to the more junior crewmember. This is an inefficient method since the result is often unpredictable.
Forward Looking
A forward looking algorithm is used in conjunction with a greedy algorithm. The forward looking algorithm looks ahead to junior crewmembers' preferences/pairing requests before awarding lines. If there are multiple legal and equally preferred lines for a senior crewmember, the algorithm will award the line that allows for the most junior crewmembers to still be satisfied.
Unstacking
Unstacking algorithms are used in conjunction with greedy algorithms to control open time (the number of uncovered pairings on each calendar date). "Stacking" occurs when awarding lines to junior crewmembers and the number pairings need to be covered on a given date is equal to the number of available crewmembers. When this happens, the available junior crewmember has to cover a pairing on that date regardless of his/her preferences. To improve this, the unstacking approach tries to see if a senior crewmember can be awarded a line on that date without sacrificing his or her satisfaction while improving the quality of a junior crewmembers line.
Global Optimization
Global Optimization is the idea that the PBS problem can be solved while taking into account all variables at once. Advanced Optimization Systems takes advantage of global optimization to award the best possible lines. Before awarding, AOS PBS (APBS) generates a huge number of preferred lines for all crewmembers, and then selects a solution that maximizes the overall crew satisfaction while taking into account company goals. Using this solution as a guideline, the core generates lines for each crewmember, starting with the most senior, and awards the best fit among these lines. The global optimization algorithm runs multiple times at different seniority levels to guarantee it always has the best guidelines for crewmember line awarding. The real spirit of using global optimization is its ability to find the best fit among the best lines. No other approach has yet to achieve that high overall satisfaction demonstrated by APBS.
FAQ/Misconceptions
"Preferential bidding systems only benefit management"
PBS is coming. It is an efficient way to operate an airline. Crewmembers should actively lead the company, negotiate the rules, and select the PBS vendor they prefer. A correct implementation benefits both the crewmembers and the company. It lets crewmembers' preferences dictate lines awarded.
"PBS only benefits senior crewmembers"
Senior crewmembers, due to their position in the airline, will get the lines they want. However, PBS allows junior crewmembers to benefit as well since the lines are created after taking into consideration everyone's preferences. This allows for the opportunity for junior crewmembers to get better lines as well. In a survey conducted by AOS, 85% of bidders had a positive experience with our PBS implementation. (4000 crewmembers of all seniority levels surveyed; 40% responded)
"You cannot bid as a line holder and reserve independently with PBS"
This is not true. AOS's PBS allows bidders to bid the independently or dynamically. This means that a junior crewmember might be quite "senior" as a reserve. He/she can bid reserve preferences in addition to his/her line holder preference. For instance, if a crewmember cannot get certain off days as a line holder, he/she can be awarded those off days as a reserve. In AOS's system, there is no need to predefine who the line holders are before awarding.
"It is difficult to learn the system and bid correctly"
Crewmembers feel like they are in the dark when they are bidding. And this is true for certain PBS systems. However, with AOS, we have a clear pairing pools and layers concept, graphical interfaces, and real-time statistics. It is very easy to use and most of our users are able to master it in about 20 minutes.
"An interactive PBS that shows available options after senior crewmembers have bid is better than the conventional 'bid and wait' approach"
Only looking at senior preferences to define your line is an outdated approach. It achieves the lowest overall satisfaction. It also encourages crewmembers to bid non-optimized leftover pairings. This kind of strategy is just like a line builder where you manual build your line after senior crewmembers have built their lines. In contrast, using a concept known as global optimization, AOS's PBS considers the preferences of all those with less seniority to award the best line.
"The company uses PBS to force crewmembers to cover more credit"
With or without PBS, there is a number of credits that must be covered by the crewmembers. PBS cannot change how many credits there are, only how they are divided. PBS awards lines to cover all pairings. How these are balanced among junior and senior crewmembers is up to the union and the company. The ability to construct high credit, legal lines, is not a fault, but an ability of PBS.
"PBS may award my preferred pairings to a more junior crewmember to make it easier to satisfy overall coverage"
A good PBS should not do this. It is a violation of seniority. A PBS may require you to work on certain days you want off, but this should also be true for everyone junior to you. A PBS should not reserve, for instance, certain pairings as fillers for junior lines in order to satisfy overall coverage.
What should the overall satisfaction rate be for a PBS?
The satisfaction rate greatly depends on how users bid. A lot of users end up bidding correctly and this can alter the results. Assuming everyone bids for what they want, the top one third should get what they prefer, the middle third should get about half of what they prefer, and the bottom third should get some of what they prefer.
My company already uses PBS. It is not my concern anymore.
Wrong. Different systems differ greatly in performance and satisfaction. As a crewmember, you can help make a change if you are not satisfied with your current system.
As a junior crewmember, what should I expect with PBS?
You probably won't be able to get weekends off as a lineholder, and most likely on Thanksgiving and Christmas. However, this is also very true in a Bid Line system. However, you should be able to get specific days off, preferred layover cities, credit hours, etc. You may also be awarded as a reserve during days you request off.
Can you go wrong with PBS?
Absolutely. A bad performing PBS, poor rules and contracts between company and crewmembers, poor training, and bad vendor services can all contribute to the failure of a PBS. Once a system is implemented. It is hard to change. It is important to deal with a company that not only has a good system, but also knows the potential pitfalls of PBS and can help you avoid them.
How much money will PBS save?
With a correct implementation of PBS, we can expect a 5-7% savings on crew in addition to the reduced operation cost due to a simplified process. All cases are different, and it is advised that a benchmark test always be performed before committing to a system.
How much does PBS cost?
The more crewmembers, the lower the average cost. Different cases can result in different prices. Usually, the cost is less than 5$ per crewmember per month. Company savings due to PBS must also be factored in when calculating overall cost.
Further questions?
Do not hesitate to contact us. Our information can be found on our website, aos.us
Vendors
If your airline has made the decision to switch to PBS, we hope that you explore all available options before settling on a vendor. Advanced Optimization Systems is willing to provide benchmark tests for your consideration. We are able to provide a Stress Bidding benchmark where all crewmembers have the same bids to ensure seniority is honored. We also provide a Reality Bidding test where there are test groups that make different bids. This mimics real world bidding where each crewmember bids based on his or her needs. We believe the results of these benchmarks will show that our system can provide high satisfaction for both junior and senior crewmembers.
If you decide to go in a different direction, here is a list of other vendors offering PBS:
AIMS
CrewingSolutions
Jeppesen/CarmenSystems
Kronos/Ad-Opt
Kernel-Software
Navtech/Airware
Sabre/Flightline
We recommend that you get a reference from their PBS crewplanners and crewmembers.