diff --git a/pyproject.toml b/pyproject.toml
index 59e9b48..41c0bad 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "cell-eval"
-version = "0.6.6"
+version = "0.6.7"
 description = "Evaluation metrics for single-cell perturbation predictions"
 readme = "README.md"
 authors = [
diff --git a/src/cell_eval/metrics/_de.py b/src/cell_eval/metrics/_de.py
index dd71626..1f2ca00 100644
--- a/src/cell_eval/metrics/_de.py
+++ b/src/cell_eval/metrics/_de.py
@@ -129,8 +129,8 @@ def __call__(self, data: DEComparison) -> dict[str, float]:
             )
             .agg(
                 pl.corr(
-                    pl.col(data.real.fold_change_col),
-                    pl.col(f"{data.real.fold_change_col}_pred"),
+                    pl.col(data.real.fold_change_col).cast(pl.Float64),
+                    pl.col(f"{data.real.fold_change_col}_pred").cast(pl.Float64),
                     method="spearman",
                 ).alias("spearman_corr"),
             )