diff --git a/binarycpython/utils/grid.py b/binarycpython/utils/grid.py
index 0c4f3ee3ac17537ea2d7a04c9b2a3eaeb19e707d..df959c4fc70cb3edfd15cfa98b75c39b317e0e16 100644
--- a/binarycpython/utils/grid.py
+++ b/binarycpython/utils/grid.py
@@ -368,7 +368,7 @@ class Population:
         probdist: str,
         dphasevol: Union[str, int],
         parameter_name: str,
-        gridtype: str = "edge",
+        gridtype: str = "centred",
         branchpoint: int = 0,
         precode: Union[str, None] = None,
         condition: Union[str, None] = None,