diff --git a/forest/sycamore/responses.py b/forest/sycamore/responses.py
index 0c62cd3f..6401fdee 100644
--- a/forest/sycamore/responses.py
+++ b/forest/sycamore/responses.py
@@ -143,7 +143,7 @@ def agg_changed_answers_summary(
     detail["time_to_answer"] = np.where(
         detail["data_stream"] == "survey_timings",
         detail["time_to_answer"],
-        np.NaN
+        np.nan
     )
 
     #####################################################################
@@ -251,7 +251,7 @@ def format_responses_by_submission(agg_data: pd.DataFrame) -> dict:
             survey_df["survey_duration"] = np.where(
                 survey_df["data_stream"] == "survey_timings",
                 survey_df["survey_duration"],
-                np.NaN
+                np.nan
             )
 
             keep_cols = ["beiwe_id", "start_time", "end_time",
diff --git a/forest/sycamore/submits.py b/forest/sycamore/submits.py
index 79af48c4..72f5bf46 100644
--- a/forest/sycamore/submits.py
+++ b/forest/sycamore/submits.py
@@ -470,12 +470,12 @@ def survey_submits(
     submit_lines3["time_to_submit"] = np.where(
         submit_lines3["submit_flg"] == 1,
         submit_lines3["time_to_submit"],
-        np.NaN
+        np.nan
     )
     submit_lines3["time_to_open"] = np.where(
         submit_lines3["opened_flg"] == 1,
         submit_lines3["time_to_open"],
-        np.NaN
+        np.nan
     )
     return submit_lines3.sort_values(["survey id", "beiwe_id"]
                                      ).drop_duplicates()