diff --git a/source/Trek-12/Models/Interfaces/IPersistence.cs b/source/Trek-12/Models/Interfaces/IPersistence.cs
index aada33b..fa0a645 100644
--- a/source/Trek-12/Models/Interfaces/IPersistence.cs
+++ b/source/Trek-12/Models/Interfaces/IPersistence.cs
@@ -1,11 +1,12 @@
 using Models.Game;
+using System.Collections.ObjectModel;
 
 namespace Models.Interfaces
 {
     public interface IPersistence
     {
-        (List<Player>, List<Game.Game>, List<Map>, List<BestScore>) LoadData();
+        (ObservableCollection<Player>, ObservableCollection<Game.Game>, ObservableCollection<Map>, ObservableCollection<BestScore>) LoadData();
         
-        void SaveData(List<Player> players, List<Game.Game> games, List<Map> maps, List<BestScore> bestScores);
+        void SaveData(ObservableCollection<Player> players, ObservableCollection<Game.Game> games, ObservableCollection<Map> maps, ObservableCollection<BestScore> bestScores);
     }
 }
\ No newline at end of file