diff --git a/backend/app.py b/backend/app.py
index 49d368b..f4da070 100644
--- a/backend/app.py
+++ b/backend/app.py
@@ -818,7 +818,12 @@ async def get_rankings(
 
     # Return only relevant fields for rankings
     available_cols = [c for c in RANKING_COLUMNS if c in df.columns]
-    df = df[available_cols]
+    df = df[available_cols].copy()
+
+    # Surface the requested metric under a stable `value` key so the
+    # frontend doesn't need to know each metric's column name. The raw
+    # metric column is also kept in the row for callers that want it.
+    df["value"] = df[metric]
 
     return {
         "metric": metric,