diff --git a/cace/parameter/parameter.py b/cace/parameter/parameter.py
index 1c57388..d767d68 100755
--- a/cace/parameter/parameter.py
+++ b/cace/parameter/parameter.py
@@ -273,7 +273,6 @@ def get_result(self, name: str):
         if name in self.results_dict:
             return self.results_dict[name]
 
-        warn(f'Could not find result {name}.')
         return None
 
     def cancel(self, no_cb):
@@ -431,6 +430,11 @@ def evaluate_result(self):
         # For each named result in the spec
         for named_result in self.param['spec']:
 
+            if not self.get_result(named_result):
+                err(f'No result "{named_result}" available.')
+                self.result_type = ResultType.ERROR
+                continue
+
             # For each entry in the specs
             for entry in ['minimum', 'typical', 'maximum']:
 
@@ -469,6 +473,8 @@ def evaluate_result(self):
                         else:
                             err(f'Unknown calculation type: {calculation}')
                     else:
+                        err(f'Result "{named_result}" is empty.')
+                        self.result_type = ResultType.ERROR
                         result = None
 
                     self.get_result(named_result).result[entry] = result
diff --git a/cace/parameter/parameter_ngspice.py b/cace/parameter/parameter_ngspice.py
index b07b25f..953a176 100755
--- a/cace/parameter/parameter_ngspice.py
+++ b/cace/parameter/parameter_ngspice.py
@@ -705,6 +705,12 @@ def __getattr__(self, attr):
 
             for variable in script_variables:
                 if variable != None:
+                    # Check for variable in results
+                    if variable not in collated_values:
+                        err(f'Variable "{variable}" not in results.')
+                        self.result_type = ResultType.ERROR
+                        return
+
                     # Extend the final result
                     self.get_result(variable).values.extend(
                         collated_values[variable]