Full Papers -- Audio Features, Precomputed for Podcast Retrieval and Information Access Experiments -- A Hybrid Approach for Stock Market Prediction Using Financial News and Stocktwits -- Dataset Creation Framework for Personalized Type-based Facet Ranking Tasks Evaluation -- SubjectivITA: An Italian Corpus for Subjectivity Detection in Newspapers -- Evaluating Elements of Web-based Data Enrichment for Pseudo-Relevance Feedback Retrieval -- End-to-end Fine-grained Neural Entity Recognition of Patients, Interventions, and Outcomes -- Comparing Traditional and Neural Approaches for detecting Health-related Misinformation -- Towards the evaluation of Information Retrieval Systems on evolving datasets with pivot systems -- A Multi-Task Learning Model for Multidimensional Relevance Assessment -- Skill Extraction for Domain-Specific Text Retrieval in a Job-Matching Platform -- Linguistic Uncertainty in Clinical NLP: a Taxonomy, Dataset and Approach -- Best of 2020 Labs -- Self-Calibrating Neural-Probabilistic Model for Authorship Verification Under Covariate Shift -- Priberam at MESINESP Multi-label Classification of Medical Texts Task -- Herbarium-Field Triplet Network for Cross-Domain Plant Identification -- BERT-based Transformers for Early Detection of Mental Health Illnesses -- Dowsing for Math Answers -- Overviews 2021 Labs -- Overview of ARQMath-2 (2021): Second CLEFLab on Answer Retrieval for Questions on Math -- Overview of BioASQ 2021: The ninth BioASQ challenge on Large-Scale Biomedical Semantic Indexing and Question Answering -- The CLEF-2021 CheckThat! Lab on Detecting Check-Worthy Claims, Previously Fact-Checked Claims, and Fake News -- Overview of ChEMU 2021: Reaction Reference Resolution and Anaphora Resolution in Chemical Patents -- Overview of the CLEF eHealth Evaluation Lab 2021 -- Overview of eRisk 2021: Early Risk Prediction on the Internet -- Overview of the ImageCLEF 2021: Multimedia Retrieval in Medical, Nature, Internet and Social Media Applications -- Overview of LifeCLEF 2021: an Evaluation of Machine-Learning based Species Identification and Species Distribution Prediction -- Overview of LiLAS 2021 - Living Labs for Academic Search -- Overview of PAN 2021: Authorship Verification, Pro ling Hate Speech Spreaders on Twitter, and Style Change Detection -- Overview of SimpleText 2021 - CLEF Workshop on Text Simplification for Scientific Information Access -- Overview of Touch e 2021: Argument Retrieval.