diff --git a/src/twomartens/masterthesis/evaluate.py b/src/twomartens/masterthesis/evaluate.py
index 070b9b1..282a15d 100644
--- a/src/twomartens/masterthesis/evaluate.py
+++ b/src/twomartens/masterthesis/evaluate.py
@@ -296,7 +296,7 @@ def get_f1_score(cumulative_precisions: List[np.ndarray],
         if not np.count_nonzero(cumulative_precision + cumulative_recall):
             cumulative_f1_scores.append([])
             continue
-        f1_score = 2 * ((cumulative_precision * cumulative_recall) / (cumulative_precision + cumulative_recall))
+        f1_score = 2 * ((cumulative_precision * cumulative_recall) / (cumulative_precision + cumulative_recall + 0.001))
         cumulative_f1_scores.append(f1_score)
     
     return cumulative_f1_scores