How videos get in

Rounds is a library of 1,097 health, medicine and biology videos: 601 recommended by 1,262 people, 113 of them clinicians, trainees or researchers, and 496 lectures from health institutions. Nobody at Rounds picks individual videos. People recommended each one on Reddit, Hacker News, Stack Exchange or Wikipedia, or a listed institution published it, and a published rule decides what is in and in what order. The idea comes from Andrej Karpathy's HackerTube, which does the same for videos recommended on Hacker News.

Rounds is for learning about health. It is not medical advice, and a recommendation is not a diagnosis or a treatment plan. Talk to a clinician about your own health.

The inclusion rule

A video is in Rounds if one of these holds:

• At least 2 different people recommended it in the sources below.
• One person recommended it and their community agreed: a Reddit comment reached a score of 10, a Reddit post 25, or a Stack Exchange answer 5. Posts need more because self-promotion usually arrives as a post.
• It was recommended on Hacker News, where HackerTube already required at least three people in three different months.
• A listed health institution uploaded it, it is a lecture, explainer, debate or clinical demonstration of at least 3 minutes, it is among that institution's 40 most-watched such uploads, and it does not advertise anything.

A video is left out if:

• more people disputed it than recommended it,
• it is shorter than 60 seconds, or its uploader does not allow it to play outside YouTube,
• it is not about health, medicine, the body or the mind,
• it only matters around one news event,
• or it argues against well-established medical consensus in a way that could cause harm, such as claiming vaccines cause autism or that a supplement cures cancer. This removed 2 videos in the current build.

A Wikipedia article in a medical WikiProject that links a video as a source or for further reading counts as one recommendation, but never gets a video in alone: anyone can add an external link, including the uploader, and in quiet articles self-added links last for years.

A link counts as a recommendation when the person points others to it: "watch this", "this helped me", a video given as the answer to a question, or a Wikipedia health article citing it. Asking whether a video is true, sharing it as news and criticizing it do not count. An uploader linking their own video never counts.

Ranking

Each person who recommended a video adds 1 plus log₂(1 + the score of their best comment or answer about it). Ten upvotes adds about 3.5, a hundred about 6.7, so one popular comment cannot outweigh several people. Hacker News comments count as 3 votes, or 10 when HackerTube labeled them a strong recommendation, and a Wikipedia citation counts as 10.

Where a recommendation comes from changes its weight: 1.5× from clinician communities, or from anyone whose flair names a health profession or research role, 1.25× from science communities and Stack Exchange's science sites, 1.5× for Wikipedia, and 1× elsewhere. Flairs are what people chose to show; r/AskDocs verifies its flairs, most communities do not.

Lasting recommendations count for more than one burst of attention: each further calendar month in which someone recommended a video adds 10% to its score, up to 100%. People who disputed it subtract half of the same weight. Institutional uploads nobody has recommended yet rank below every community pick.

The home page is a weighted shuffle, new on every visit: each video's chance of coming first is proportional to its score raised to the power 1.5, so the most recommended videos lead often but not every time, and videos further down get seen. Scrolling and chips keep one visit's order. Area, topic and channel pages, "Most recommended" in search and the Recently recommended filter keep the ranked order.

Feeds never put two videos from the same channel within four places, so one prolific channel cannot fill a screen.

Sources

Choosing these sources and their tiers, and choosing the institutions below, are the editorial decisions in Rounds. The rule decides the rest.

Still being read: r/medicine, r/Residency, r/medicalschool, r/nursing, r/pharmacy, r/physicaltherapy (comments), r/emergencymedicine (comments), r/Psychiatry (comments), r/FamilyMedicine (comments), r/Cardiology (comments), r/neurology (comments), r/dietetics (comments), r/ems, r/epidemiology (comments), r/publichealth (comments), r/AskDocs (comments), r/ScientificNutrition, r/AdvancedFitness, r/StrongerByScience, r/neuroscience, r/askscience (comments), r/longevity, r/biology, r/Physiology, r/Biohackers, r/Nootropics, r/Supplements, r/QuantifiedSelf, r/PeterAttia, r/HubermanLab, r/nutrition, r/Fitness, r/xxfitness, r/loseit, r/intermittentfasting, r/sleep, r/insomnia, r/ADHD, r/diabetes, r/migraine, r/ChronicPain, r/Menopause, r/Semaglutide. A community's posts and its comments each count once their whole history is read, so a half-read history never tilts the ranking toward the years read first.

Stack Exchange sites: Medical Sciences Stack Exchange, Biology Stack Exchange, Psychology & Neuroscience Stack Exchange, Skeptics Stack Exchange, Physical Fitness Stack Exchange. Wikipedia: articles tagged by WikiProject Medicine, Pharmacology, Physiology, Neuroscience, Nutrition or Anatomy.

Health institutions: NIH VideoCast, National Institutes of Health (NIH), CDC, World Health Organization (WHO), Stanford Medicine 25, Stanford Medicine, Harvard Medical School, Johns Hopkins Medicine, Mayo Clinic, Cleveland Clinic, UCSF, University of California Television (UCTV), Yale Courses, Duke Health, NEJM Group, JAMA Network, The BMJ, Cochrane, iBiology Science Stories, Khan Academy Medicine, American Heart Association, Buck Institute. They fall in the categories the National Academy of Medicine named as credible sources of health information online in 2021: government health agencies, accredited medical schools and health systems, peer-reviewed journals, and health nonprofits.

Reddit history comes from the Arctic Shift archive, Hacker News from HackerTube's dataset (ODC-By 1.0), Stack Exchange and Wikipedia from their public APIs. The newest recommendation considered is from Nov 1, 2026. Video details come from the YouTube Data API.

What the model labels

A language model (Gemini Flash) reads each video's title and description and the comments that link it. It labels the health area, topics, kind of video, audience and shelf life; names the presenter only as the video describes them; marks uploads that sell something, topics that experts debate, and claims against medical consensus; writes the one-line summary and a plain title; and marks each comment as a recommendation, a mention, a dispute or self-promotion.

The rule above, not the model, decides what gets in, with one exception: the consensus label can keep a video out, as described in the rule. The model does not watch videos or check their claims, so labels describe what a video and its description say, not whether it is right. The comments themselves are on every watch page under "Why it's here", so you can check every label.

Counted, not labeled: the papers linked in a description, chapters, and the moments people linked to.

Limits

• Popular is not the same as correct. Disputes are shown, and labels flag products and debated claims, but a well-liked video can still be wrong.
• Communities weigh some subjects far more than others. Fitness and nutrition have many recommendations; rare conditions have few.
• Old videos may describe superseded guidance. Watch pages mark uploads that may be out of date.
• Recent videos have had less time to collect recommendations, so they rank lower at first. The Recently recommended filter helps.
• Forums outside these sources, podcasts without YouTube versions and paywalled lectures are not included.

Download the dataset

The full ranking is free to download: every video id with its labels, recommendation counts, score and the links to the comments behind it. YouTube's terms do not allow redistributing titles and other video details, so the file has video ids only. There is also an RSS feed of the newest additions.

Download dataset.jsonBuilt Nov 2, 2026

Privacy

Rounds has no accounts. Your history, likes, Watch later and playlists stay in this browser's storage and never reach a server, so nothing you watch about your health leaves your device. Videos play through YouTube's privacy-enhanced player (youtube-nocookie.com), which YouTube says does not store viewing information until you play a video. Clearing site data removes everything.

Rounds is not affiliated with YouTube, Google, Reddit, Hacker News, Stack Exchange, Wikipedia or any institution listed here. Videos remain on YouTube under their uploaders' terms. Back to videos