diff --git a/src/GmRelay.Web/Services/ISessionStore.cs b/src/GmRelay.Web/Services/ISessionStore.cs
index d36000a..07e6999 100644
--- a/src/GmRelay.Web/Services/ISessionStore.cs
+++ b/src/GmRelay.Web/Services/ISessionStore.cs
@@ -27,4 +27,18 @@ public interface ISessionStore
     Task RemoveGroupCoGmAsync(Guid groupId, long coGmTelegramId);
     Task<List<WebParticipant>> GetSessionParticipantsAsync(Guid sessionId);
     Task RemovePlayerFromSessionAsync(Guid sessionId, Guid groupId, Guid participantId);
+    Task<List<PlayerAttendanceStats>> GetGroupAttendanceStatsAsync(Guid groupId);
+
+public sealed record PlayerAttendanceStats(
+    Guid PlayerId,
+    string DisplayName,
+    string? TelegramUsername,
+    long TotalSessions,
+    long ConfirmedCount,
+    long DeclinedCount,
+    long NoResponseCount,
+    long WaitlistedCount,
+    long CancellationAffectedCount,
+    decimal AttendanceRate
+);
 }