publications

2026

1. RecSys workshop paper

   The Disconnect Between Better Descriptive Reasoning Trace Quality and Recommendation Effectiveness

   Penha, Gustavo, Elenter, Juan, Hauff, Claudia, Bouchard, Hugues, Bennett, Paul, and Lalmas, Mounia

   PDF
2. RecSys workshop paper

   From IR to RecSys: Evaluating LLM-based Judges in Cranfield-style Recommendation Collections

   Penha, Gustavo, Petrov, Aleksandr V., Hauff, Claudia, Palumbo, Enrico, Vardasbi, Ali, D’Amico, Edoardo, Fabbri, Francesco, Wang, Alice, Chandar, Praveen, Lindstrom, Henrik, Bouchard, Hugues, and Lalmas, Mounia

   PDF
3. SIGIR short paper

   As It Was: Aligning LLM Search Evaluation with Historical User Preferences

   Vardasbi, Ali, Penha, Gustavo, Palumbo, Enrico, Hauff, Claudia, Bouchard, Hugues, and Lalmas, Mounia

   PDF
4. KDD industry track

   Deploying Semantic ID-based Generative Retrieval for Large-Scale Podcast Discovery at Spotify

   D’Amico, Edoardo, Nadai, Marco De, Chandar, Praveen, Vohra, Divita, Lin, Shawn, Lefarov, Max, Gigioli, Paul, Penha, Gustavo, and others,

   PDF

2025

1. workshop paper

   Stream: Scaling up Mechanistic Interpretability to Long Context in LLMs via Sparse Attention

   Rosser, J, García, José Luis Redondo, Penha, Gustavo, Palla, Konstantina, and Bouchard, Hugues

   PDF
2. EARL@RecSys workshop paper

   AudioBoost: Increasing Audiobook Retrievability in Spotify Search with Synthetic Query Generation

   Palumbo, Enrico, Penha, Gustavo, Liu, Alva, Eltscheminov, Marcus, Carvalho, Jefferson, Wang, Alice, Bouchard, Hugues, Corona Pampin, Humberto Jesús, and Tran Luu, Michelle

   PDF
3. RecSys LBR track

   Evaluating Podcast Recommendations with Profile-Aware LLM-as-a-Judge

   Fabbri, Francesco, Penha, Gustavo, D’Amico, Edoardo, Wang, Alice, De Nadai, Marco, Doremus, Jackie, Gigioli, Paul, Damianou, Andreas, Stal, Oskar, and Lalmas, Mounia

   PDF
4. RecSys LBR track

   Semantic IDs for Joint Generative Search and Recommendation

   Penha, Gustavo, D’Amico, Edoardo, De Nadai, Marco, Palumbo, Enrico, Tamborrino, Alexandre, Vardasbi, Ali, Lefarov, Max, Lin, Shawn, Heath, Timothy, Fabbri, Francesco, and others,

   PDF
5. BIAS@SIGIR workshop paper

   Adaptive Repetition for Mitigating Position Bias in LLM-Based Ranking

   Vardasbi, Ali, Penha, Gustavo, Hauff, Claudia, and Bouchard, Hugues

   PDF
6. pre-print

   Aligned Query Expansion: Efficient Query Expansion for Information Retrieval through LLM Alignment

   Yang, Adam, Penha, Gustavo, Palumbo, Enrico, and Bouchard, Hugues

   PDF Blog
7. ECIR industry track

   Contextualizing Spotify’s Audiobook List Recommendations with Descriptive Shelves

   Penha, Gustavo, Wang, Alice, Achenbach, Martin, Sheets, Kristen, Mantravadi, Sahitya, Galvez, Remi, Guetta-Jeanrenaud, Nico, Narayanan, Divya, Kalaydzhyan, Ofeliya, and Bouchard, Hugues

   Abs PDF

   In this paper, we propose a pipeline to generate contextualized list recommendations with descriptive shelves, in the domain of audiobooks. By creating several shelves for topics the user has an affinity to, e.g. “Uplifting Women’s Fiction”, we can help them explore their recommendations according to their interests and at the same time recommend a diverse set of items. To do so, we use Large Language Models (LLMs) to enrich each item’s metadata based on a taxonomy created for this domain. Then we create diverse descriptive shelves for each user. A/B tests show improvements in user engagement and audiobook discovery metrics, demonstrating benefits for users and content creators.

8. pre-print

   Text2Tracks: Prompt-based Music Recommendation via Generative Retrieval

   Palumbo, Enrico*, Penha, Gustavo*, Damianou, Andreas, Garcı́a, José Luis Redondo, Heath, Timothy Christopher, Wang, Alice, Bouchard, Hugues, and Lalmas, Mounia

   PDF Blog

2024

1. RecSys

   Bridging Search and Recommendation in Generative Retrieval: Does One Task Help the Other?

   Penha, Gustavo, Vardasbi, Ali, Palumbo, Enrico, Nadai, Marco, and Bouchard, Hugues

   PDF Blog Slides
2. CIKM industry track

   PODTILE: Facilitating Podcast Episode Browsing with Auto-generated Chapters

   Ghazimatin, Azin, Garmash, Ekaterina, Penha, Gustavo, Sheets, Kristen, Achenbach, Martin, Semerci, Oguz, Galvez, Remi, Tannenberg, Marcus, Mantravadi, Sahitya, Naraynan, Divya, Kalaydzhyan, Ofeliya, Cole, Douglas, Carterette, Ben, Clifton, Ann, Bennet, Paul, Hauff, Claudia, and Lalmas, Mounia

   PDF Blog

2023

1. TheWebConf

   Improving Content Retrievability in Search with Controllable Query Generation

   Penha, Gustavo, Palumbo, Enrico, Aziz, Maryam, Wang, Alice, and Bouchard, Hugues

   PDF Blog Slides
2. ECIR

   Do the Findings of Document and Passage Retrieval Generalize to the Retrieval of Responses for Dialogues?

   Penha, Gustavo, and Hauff, Claudia

   PDF Code

2022

1. CHI late-break. work

   Helping Voice Shoppers Make Purchase Decisions

   Penha, Gustavo, Krikon, Eyal, Murdock, Vanessa, and Avula, Sandeep

   PDF Poster
2. CHIIR short paper

   Pairwise Review-Based Explanations for Voice Product Search

   Penha, Gustavo, Krikon, Eyal, and Murdock, Vanessa

   PDF Poster
3. ECIR 🏆 best paper

   Evaluating the Robustness of Retrieval Pipelines with Query Variation Generators

   Penha, Gustavo, Câmara, Arthur, and Hauff, Claudia

   PDF Code Slides

2021

1. EACL

   On the Calibration and Uncertainty of Neural Learning to Rank Models for Conversational Search

   Penha, Gustavo, and Hauff, Claudia

   PDF Code Slides
2. ECIR short paper

   Weakly Supervised Label Smoothing

   Penha, Gustavo, and Hauff, Claudia

   PDF Code Slides

2020

1. SCAI workshop paper

   Slice-Aware Neural Ranking

   Penha, Gustavo, and Hauff, Claudia

   PDF Code Slides
2. RecSys

   Probing BERT for Conversational Recommendation

   Penha, Gustavo, and Hauff, Claudia

   PDF Code Slides
3. RecSys 🏆 best paper RU

   Exploiting Performance Estimates for Augmenting Recommendation Ensembles

   Penha, Gustavo, and Santos, Rodrygo

   PDF Code Slides
4. KDD’Converse workshop paper

   Challenges in the Evaluation of Conversational Search Systems

   Penha, Gustavo, and Hauff, Claudia

   PDF Slides
5. CAIR workshop paper

   Domain Adaptation for Conversation Response Ranking

   Penha, Gustavo, and Hauff, Claudia

   PDF Code Slides
6. ECIR

   Curriculum Learning Strategies for IR: An Empirical Study on Conversation Response Ranking

   Penha, Gustavo, and Hauff, Claudia

   PDF Code Slides

2019

1. pre-print

   Introducing MANtIS: a novel multi-domain information seeking dialogues dataset

   Penha, Gustavo, Balan, Alexandru, and Hauff, Claudia

   arXiv preprint arXiv:1912.04639

   PDF Code Website
2. RecSys

   Online learning to rank for sequential music recommendation

   Pereira, Bruno L, Ueda, Alberto, Penha, Gustavo, Santos, Rodrygo LT, and Ziviani, Nivio

   PDF
3. ECIR short paper

   Document performance prediction for automatic text classification

   Penha, Gustavo, Campos, Raphael, Canuto, Sérgio, Gonçalves, Marcos André, and Santos, Rodrygo LT

   PDF Poster