Recommendation Systems (RecSys)

A one-stop shop for all things RecSys.
📌 Table of Contents
overview; retrieval; ranking
neural colab filtering; matrix factorization
RecSys Toolkit
embedding space; alternating least squares; matrix factorization; mean normalization
Candidate Generation
notation; content-based filtering; code deep-dive; collaborative filtering; code deep-dive; retrieval
Ranking / Scoring
overview; scoring with the candidate generator?; objective function for scoring; position/selection bias
overview; freshness; diversity; fairness
platt scaling; isotonic regression; Bayesian calibration
RecSys Architectures
Deep and Cross; Deep and Wide; NCF; Deep FM; Two Towers
Building a Music Recommendation System using PySpark
code deep-dive; data preprocessing; data aggregation; data split; spin up your model!
Evaluation Metrics, Testing, and Loss Functions for Recommender Systems
evaluating candidate generation; evaluating scoring; evaluating ranking; A/B testing
Content Moderation for Recommender Systems
videos, text, and image moderation; early and late moderation
GNNs for Recommender Systems
GraphSage; Edge GNNs; use-cases
Summary of Relevant Papers
popular recommendation systems in production demystified
Recommender System Bias
reasons for position bias; measuring positional bias; mitigation strategies
Cold Start Problem
types of cold start; mitigation strategies
Multi-Armed Bandit
exploration; exploitation; contextual bandit
Multi-objective Optimization
LinkedIn use-case; overview
📖 References
📝 Citation
If you found our work useful, please cite it as:
  author        = {Chadha, Aman and Jain, Vinija},
  title         = {Recommender Systems Primer},
  howpublished  = {\url{}},
  year          = {2022},
  note          = {Accessed: 2022-07-01},
  url           = {}

A. Chadha, V. Jain, Notes for Recommendation Systems, 2022, Accessed: July 1 2022.