diff --git a/CLAUDE.md b/CLAUDE.md
index 0a94065..05205eb 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -107,3 +107,20 @@ Use `.card-empty-center` class for all "No …" messages inside cards.
 - `src/lib/popupStyles.js` — modal overlay/surface styles
 - `api/filebrowser.js` — file browser API (Vercel serverless)
 - `supabase/functions/fbq-proxy/` — Supabase edge function for FileBrowser Quantum
+
+## Team Performance calculation
+
+Source: `deliveries` table (not `tasks`).
+
+Each row in `deliveries` = one unit of work by one person:
+- `sent_by` — name of person who submitted the work
+- `version_number` — 0 = new task delivery, 1+ = revision delivery
+- `sent_at` — when submitted (bucketed by EST month)
+
+Rules:
+- R00 → `newCount += 1` for `sent_by`
+- R01, R02, R03… → `revCount += 1` each for `sent_by`
+- Same task can have deliveries by different people — each counts independently
+- Task status is **ignored** — a delivery record means work was done regardless of current task status (task goes back to `not_started` when revision is requested)
+- Top 5 by total (new + revisions) shown per month
+- Months shown only if delivery data exists for that month (EST timezone)