For now the index measures long-form videos only (not Shorts, as YouTube defines them). Shorts are not measured. The daily API quota cannot cover a baseline for every Short that enters the charts, so Shorts are out of scope until the budget allows. The charts are still read in full.
The published series starts on 2026-09-27.
The Institute for Open Social Analytics (IOSA) is an independent, self-funded research project with no profit purpose, measuring public social media metrics against each channel's own statistical baseline. Trend data is open access. Optional commemorative items fund our servers, API quota and development. IOSA is fully independent and is not affiliated, endorsed, associated, or partnered with YouTube, TikTok, Instagram, X (Twitter), or Meta.
Did Your Content Outperform Statistical Baselines?
Search a handle or a video link among the long-form videos first observed in YouTube's Most Popular charts.
How to read a VPI level
To enter Most Popular a video needs absolute views, so the VPI it needs depends on the size of its channel. Most records come from large channels, where the median VPI is low; the high levels come almost entirely from small channels. Below, the median VPI on the first day observed, per channel baseline band, long-form videos only.
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Walk through this week's Most Popular in 3D. Find your channel.
HOW THE INDEX IS BUILT
A full reading of 34 countries and the 13 category charts that return data
1. One reading a day
Every day at 23:59 UTC we read every Most Popular category chart of 34 countries through the official YouTube Data API v3. For now a record opens only for long-form videos (not Shorts, as YouTube defines them). A video enters the index the first day we observe it in a chart.
2. Against its own channel
VPI divides a video's views by the median of the same channel's videos of the same format, published 7 to 90 days before it. Nothing is filtered on VPI: every video we observe is recorded.
3. Rankings
The ranking by VPI is read on the first day each video is observed, the one reading every record has. VPI is not age-adjusted.