Fairness in PCA-Based Recommenders

Fairness in PCA-Based Recommenders

From Data Skeptic by Kyle Polich

January 26, 2026 · 50 min

About this episode

The episode discusses algorithmic fairness in recommender systems with insights from David Liu on PCA and collaborative filtering.

In this episode, we explore the fascinating world of recommender systems and algorithmic fairness with David Liu, Assistant Research Professor at Cornell University's Center for Data Science for Enterprise and Society. David shares insights from his research on how machine learning models can inadvertently create unfairness, particularly for minority and niche user groups, even without any malicious intent. We dive deep into his groundbreaking work on Principal Component Analysis (PCA) and collaborative filtering, examining why these fundamental techniques sometimes fail to serve all users equally. David introduces the concept of "power niche users" - highly active users with specialized interests who generate valuable data that can benefit the entire platform. We discuss his paper "When Collaborative Filtering Is Not Collaborative," which reveals how PCA can over-specialize on popular content while neglecting both niche items and even failing to properly recommend popular artists to new potential fans. David presents solutions through item-weighted PCA and thoughtful data upweighting strategies that can improve both fairness and performance simultaneously, challenging the common…

People in this episode

Host: Kyle Polich

Guest: David Liu

Topics covered

  • recommender systems
  • algorithmic fairness
  • machine learning
  • Principal Component Analysis
  • collaborative filtering
  • data science

Keywords

  • recommender systems
  • algorithmic fairness
  • PCA
  • collaborative filtering
  • machine learning
  • power niche users
  • data upweighting

Mentioned in this episode

Organizations: Cornell University, Meta

Books & works: When Collaborative Filtering Is Not Collaborative

More episodes of Data Skeptic

Explore listener stats, chart rankings, contacts and more on the Data Skeptic podcast page.