diff --git a/miscplot/variability.py b/miscplot/variability.py
index aff667d..51b7e3a 100644
--- a/miscplot/variability.py
+++ b/miscplot/variability.py
@@ -62,7 +62,7 @@ def variability_plot(
     df = polars.DataFrame(data_table)
 
     # Drop nulls and nans so that the boxplots don't disappear
-    df = polars.drop_nulls(subset=[data_col]).drop_nans(subset=[data_col])
+    df = df.drop_nulls(subset=[data_col]).drop_nans(subset=[data_col])
 
     # Assign category indicies (x_pos)
     df = df.sort(groups)