diff --git a/fluegg/simulation.py b/fluegg/simulation.py
index 77271417d86f5e437544f29dbe31d6f0fa47c86f..37d9da6f6b6dc70b97262218831e1351a1391001 100644
--- a/fluegg/simulation.py
+++ b/fluegg/simulation.py
@@ -193,7 +193,8 @@ class SimulationParameters:
             'varying_dd',
             'density',
             'diameter',
-            'sim_name']
+            'sim_name',
+            'results_type']
 
         # create dictionary from the valid keys
         init_values = [None] * len(valid_keys)
@@ -399,6 +400,13 @@ class SimulationParameters:
             else:
                 raise ValueError('sim_name must be type str')
 
+        # Results type
+        elif key == "results_type":
+            if isinstance(value, str):
+                return
+            else:
+                raise ValueError('results_type must be type str')
+
     def generate_sim(self):
 
         d = self.get_dict()