diff --git a/src/mdevaluate/correlation.py b/src/mdevaluate/correlation.py
index e833b41..7e89b3d 100644
--- a/src/mdevaluate/correlation.py
+++ b/src/mdevaluate/correlation.py
@@ -278,11 +278,11 @@ def van_hove_self(
     if axis == "all":
         delta_r = (vectors**2).sum(axis=1) ** 0.5
     elif axis == "xy" or axis == "yx":
-        return (vectors[:, [0, 1]]**2).sum(axis=1) ** 0.5
+        delta_r = (vectors[:, [0, 1]]**2).sum(axis=1) ** 0.5
     elif axis == "xz" or axis == "zx":
-        return (vectors[:, [0, 2]]**2).sum(axis=1) ** 0.5
+        delta_r = (vectors[:, [0, 2]]**2).sum(axis=1) ** 0.5
     elif axis == "yz" or axis == "zy":
-        return (vectors[:, [1, 2]]**2).sum(axis=1) ** 0.5
+        delta_r = (vectors[:, [1, 2]]**2).sum(axis=1) ** 0.5
     elif axis == "x":
         delta_r = np.abs(vectors[:, 0])
     elif axis == "y":