diff --git a/app/models/irt_model.py b/app/models/irt_model.py
index 2f79776..670be6f 100644
--- a/app/models/irt_model.py
+++ b/app/models/irt_model.py
@@ -1,11 +1,11 @@
 from pydantic import BaseModel
-from typing import Dict
+from typing import Dict, Optional
 
 
 class IRTModel(BaseModel):
-    a_param: float
+    a_param: Optional[float] = None
     b_param: Dict = {"schema_bson_id": str, "field_bson_id": str}
-    c_param: float
+    c_param: Optional[float] = None
     model: str
 
     def formatted_b_param(self):