Major eCommerce and online advertising platforms (such as Amazon, Spotify) can be thought of as two-sided platforms, with customers on one side and producers on the other. Traditionally, recommendation protocols of these platforms are customer-centric---focusing on maximizing customer satisfaction by tailoring the recommendation according to the personalized preferences of individual customers. However, this may lead to unfair distribution of exposure among the producers and adversely impact their well-being. As more and more people depend on such platforms to earn a living, it is important to strike a balance between fairness among the producers and customer satisfaction.
We propose to adopt the solution concepts from the fair allocation literature in order to quantify fairness/satisfaction and provide provable guarantees. In fact, the problem of two-sided fairness in recommendation can be formulated as a matroid constrained fair allocation problem. This problem naturally captures a number of other resource-allocation applications, including budgeted course allocation, graph partition, and allocation of cloud computing resources. Our main contribution is to develop polynomial-time algorithms for fair allocation of indivisible items (with formal guarantees on fairness and feasibility) in several practical scenarios which can be formulated as matroid constrained problems. In this talk, I’ll discuss the matroid constrained fair allocation problem, and show how the solutions can be applied to ensure a two-sided fair recommendation.
1. #GHCI19
Two-Sided Fairness Guarantees for
Recommendation Protocols in B2C Ecommerce Platforms
Computational Social Choice Meets Recommendation Paradigm
Arpita Biswas | arpita.biswas@live.in
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Talk Outline
Recommendation System
Fair Allocation of Indivisible Goods
Fair Allocation Under Cardinality Constraint
Two-Sided Fair Recommendation
Theoretical and Experimental Results
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Recommendation System
• Algorithms that suggest relevant items to users
— Movies to watch
— News articles to read
— Products to buy
• An efficient recommendation system is the most critical component
of most of the e-commerce and online advertisement platforms.
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Recommendation System
Post-processing
Recommendation
Algorithm
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Recommendation System
Post-processing
Image Courtesy: https://i.pinimg.com/originals/2e/b0/71/2eb071631c5fa6c710bc7f17408dd290.png
Learning Relevance
scores:
1. Content-Based
recommendations
2. Collaborative
recommendations
3. Hybrid Approaches
Relevance Scores
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Recommendation System
Post-processing
Image Courtesy: https://i.pinimg.com/originals/2e/b0/71/2eb071631c5fa6c710bc7f17408dd290.png
Popular post-
processing
technique
Top-k
recommendation
Relevance Scores
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Recommendation System in B2C Ecommerce
Multiple Stakeholders
• Producers
— of goods and services (e.g. restaurants on Google Local, hosts onAirbnb)
• Customers
— users of the platform , who consume the services
• Platform
— which sits at the center of the recommendation ecosystem, essentially
accessing the information from the user and suggesting services
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Recommendation System
Post-processing
Image Courtesy: https://i.pinimg.com/originals/2e/b0/71/2eb071631c5fa6c710bc7f17408dd290.png
Popular post-
processing
technique
Top-k
recommendation
Relevance Scores
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Computational Social Choice Meets
Recommendation Paradigm
A novel approach towards ensuring fairness among
all individuals in a two-sided market
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Recommendation
Algorithm
Fair Allocation
of Indivisible Goods
Data
Fair
Recommendation
Computational Social Choice Meets
Recommendation Paradigm
Relevance scores
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Computational Social Choice Meets
Recommendation Paradigm
Recommendation
Algorithm
Fair Allocation
of Indivisible Goods
Data
Fair
Recommendation
Computational Social ChoiceTheory
Relevance scores
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Fair Allocation of Indivisible Goods
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Fair Allocation of Indivisible Goods
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Fairness Notions
• DC Foley (1967). Resource allocation in the public sector. Yale Economic Essays, 7:73–76.
• Hal R Varian (1974). Equity, Envy, and Efficiency. Journal of Economic Theory, 9(1):63–91.
• Walter Stromquist (1980). How to Cut a Cake Fairly. The American Mathematical Monthly, 87(8):640–644.
• Steinhaus, H. (1948). The problem of fair division. Econometrica, 16:101–104.
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Fairness Notions
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Fairness Notions
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Fairness Notions
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Envy-Freeness up to One Good (EF1)
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Envy-Freeness up to One Good (EF1)
RelatedWork
• R. Lipton, E. Markakis, E. Mossel, and A. Saberi (2004). On Approximately Fair Allocations of Indivisible Goods. EC, pages 125-131.
• I. Caragiannis, D. Kurokawa, H. Moulin, A. Procaccia, N. Shah, and J. Wang (2016). The Unreasonable Fairness of Maximum Nash Welfare. EC, pages 305–322.
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MaxiMin Share Fairness (MMS)
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MaxiMin Share Fairness (MMS)
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Maximin ShareThreshold
MaxiMin Share Fairness (MMS)
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Maximin ShareThreshold
MaxiMin Share Fairness (MMS)
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MaxiMin Share Fairness (MMS)
RelatedWork
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Fair Allocation under Cardinality Constraint
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Fair Allocation under Structured Set Constraints
Existence and Algorithmic Results for:
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Computational Social Choice Meets
Recommendation Paradigm
Recommendation
Algorithm
Fair Allocation
of Indivisible Goods
Data
Fair
Recommendation
Computational Social ChoiceTheory
Relevance scores
are the valuations
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Two-Sided Fairness
for Recommendation
Protocols
Customers
Producers
Burgers
Image Courtesy: Google Images
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Two-Sided Fairness
This work is done in collaboration with IIT Kharagpur (Gourab K. Patro and Prof. Niloy Ganguly) and
Max Planck Institute for Software Systems, Germany (Abhijnan Chakrab0rty and Prof. Krishna P. Gummadi)
Experimental Results on Google Local Ratings Dataset (GL):
Customer-side (un)fairness measure
11172 customers, 855 businesses, and 25686 reviews
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Two-Sided Fairness
This work is done in collaboration with IIT Kharagpur (Gourab K. Patro and Prof. Niloy Ganguly) and
Max Planck Institute for Software Systems, Germany (Abhijnan Chakrab0rty and Prof. Krishna P. Gummadi)
Experimental Results on Google Local Ratings Dataset (GL):
Producer-side fairness measureCustomer-side (un)fairness measure
11172 customers, 855 businesses, and 25686 reviews
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References
• Fair Allocation:
— Matroid Constrained Fair Allocation Problem. Biswas and Barman AAAI’19
— Fair Allocation under Cardinality Constraint. Biswas and Barman IJCAI’18
— Groupwise Maximin Share Fair Allocation of Indivisible Goods. Barman et al. AAAI’18
• Fair Classification:
— Fairness Through the Lens of Proportional Equality. Biswas and Mukherjee AAMAS’19
— Ensuring Fair Predictions under Prior Probability Shifts. Joint work with Suvam Mukherjee*
— Quantifying Infra-marginality and Its Trade-Offs with Group Fairness. Joint work with
Siddharth Barman, Amit Deshpande, Amit Sharma*
— Fairness Guarantees in Mental Health. In collaboration with Microsoft Research Cambridge*
* work in progress
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Fairness in Recommendation
Related Work:
• Customer-based fairness
• Producer-based fairness
• Two-sided group fairness
Editor's Notes
Good morning everyone. It is really an honor for me to share my research at the Grace Hopper Celebration. This event is very close to my heart and I am thankful to Anita Borg organization and ACM India for organizing this wonderful event.
I am Arpita, I am a Google PhD Fellow at the Indian Institute of Science. My research lies in the intersection of algorithmic game theory and machine learning. Today I’m going to speak about two-sided fairness guarantees for recommendation protocols in B2C ecommerce platforms.
Here’s the outline of my talk. I’ll start by describing what is a recommendation system. Then, I’ll spend some time describing the problem of fair allocation of indivisible goods and its constrained settings. Then I’ll show how one can leverage the fair allocation problem to solve fairness in recommendation systems. I’ll conclude by listing some of the exciting results that we have so far.
In a very general way, recommender systems are algorithms aimed at suggesting relevant items to users (items being movies to watch, news articles to read, products to buy, etc.). Nowadays, recommender systems are unavoidable in our daily online journeys, mainly because of the rise of online platforms such as Amazon, Netflix, YouTube, and food delivery apps.
An efficient recommendation system is the most critical component of several e-commerce (suggest to buyers articles that could interest them) to online advertisement (suggest to users the right contents, matching their preferences), a
Let us look at a scenario to understand the recommendation process.
To create this personalized playlist for the user, the online music service runs a recommendation algorithm
This task typically requires learning the relevance scoring functions.
Traditionally, the goal of personalized recommendations have been to recommend products that would be most relevant to a customer.
Once the relevance scores are predicted, the standard practice across several recommender systems is to recommend the top-k relevant items.
While this top-k approach maximizes the satisfaction of individual customers, it may not be the best post-processing technique when it comes to B2C e-commerce platforms where the platforms need to balance producer satisfaction as well as customer satisfaction.
There are multiple stakeholders in these platforms: (i) producers of goods and services (e.g.,restaurants on Google Local, hosts on Airbnb), (ii) customers who consume them, and (iii) the platform which sits at the center of the ecosystem, essentially controlling the information access through recommendation services.
New songs/artists will never be recommended.
We propose…
Recall that the post-processing is an important step in the recommendation system workflow. Our contribution is to consider this post-processing step as being a solution to the problem of fair allocation of indivisible goods.
This problem stems from the theory of computational social choice where the goal is to find solutions that aim to provide welfare of individuals instead of solely maximizing revenue.
This problem find its application in several real-world…