diff --git a/pyciemss/integration_utils/observation.py b/pyciemss/integration_utils/observation.py
index f48061f2..56d04d7c 100644
--- a/pyciemss/integration_utils/observation.py
+++ b/pyciemss/integration_utils/observation.py
@@ -46,7 +46,7 @@ def check_data(data_path: Union[str, pd.DataFrame]):
             raise ValueError("Dataset cannot contain NaN or empty entries.")
 
         # Check that there is no missing data in the form of None type or char values
-        if not data_df.applymap(lambda x: isinstance(x, (int, float))).all().all():
+        if not data_df.map(lambda x: isinstance(x, (int, float))).all().all():
             raise ValueError(
                 "Dataset cannot contain None type or char values. All entries must be of type `int` or `float`."
             )