The Webis-CMV-20 dataset comprises all available posts and comments in the ChangeMyView subreddit from the foundation of the subreddit in 2005, until September 2017. From these, we have derived two sub-datasets for the tasks of persuasiveness prediction, and opinion malleability prediction. In addition, the corpus comprises historical posts by CMV authors, and derived personal characteristics. Dataset specification All files are in bzip2-compressed JSON Lines format. threads.jsonl: contains all the selected discussion threads from CMV pairs.jsonl: each record contains submission, delta-comment and nondelta-comment and the comments' similarity score posts-malleability.jsonl: contains posts for opinion mallebility prediction, in the format provided in the original Reddit Crawl dataset author_entity_category.jsonl: each record contains the author and list of Wikipedia entities mentioned by the author in the messages across all subreddits. For each mentioned entity we provide the following data: [title, wikidata_id, wikipedia_page_id, mentioned_entity_title, wikifier_score, subreddit_name, subreddit_id, subreddit_category_name, subreddit_topcategory_name] author_liwc.jsonl: personality traits features computed with LIWC for the authors from pairs.jsonl and post_malleability.jsonl datasets author_subreddit.jsonl: for each author statistics of all number of all posts (submissions/comments) across all subreddits are provided author_subreddit_category.jsonl: similar to author_subreddit.jsonl, the statistics of all author posts is grouped by top-categories and categories according to snoopsnoo.com