diff --git a/document/FlashcardDocumentSampler.py b/document/FlashcardDocumentSampler.py
index 3cdf9d1..a8a1f96 100644
--- a/document/FlashcardDocumentSampler.py
+++ b/document/FlashcardDocumentSampler.py
@@ -2,13 +2,13 @@ from .FlashcardDocument import FlashcardDocument
 from recsim import document
 
 class FlashcardDocumentSampler(document.AbstractDocumentSampler):
-  def __init__(self, doc_ctor=FlashcardDocument, **kwargs):
-    super(FlashcardDocumentSampler, self).__init__(doc_ctor, **kwargs)
+  def __init__(self, doc_ctor=FlashcardDocument, seed=0, **kwargs):
+    super(FlashcardDocumentSampler, self).__init__(doc_ctor, seed, **kwargs)
     self._doc_count = 0
 
   def sample_document(self):
     doc_features = {}
     doc_features['doc_id'] = self._doc_count
-    doc_features['difficulty'] = self._rng.uniform(0, 5, (1, 3))
+    doc_features['difficulty'] = self._rng.uniform(0, 3, (1, 3))
     self._doc_count += 1
     return self._doc_ctor(**doc_features)
\ No newline at end of file
diff --git a/main.py b/main.py
index 7cef75c..fe9ca21 100644
--- a/main.py
+++ b/main.py
@@ -17,8 +17,8 @@ tf.compat.v1.disable_eager_execution()
 create_agent_fn = create_agent_helper(full_slate_q_agent.FullSlateQAgent)
 
 ltsenv = environment.Environment(
-  FlashcardUserModel(num_candidates, time_budget, slate_size),
-  FlashcardDocumentSampler(),
+  FlashcardUserModel(num_candidates, time_budget, slate_size, seed=0, sample_seed=0),
+  FlashcardDocumentSampler(seed=0),
   num_candidates,
   slate_size,
   resample_documents=False)
diff --git a/user/FlashcardUserModel.py b/user/FlashcardUserModel.py
index 0ef3e06..959d306 100644
--- a/user/FlashcardUserModel.py
+++ b/user/FlashcardUserModel.py
@@ -7,13 +7,14 @@ from util import eval_result
 import numpy as np
 
 class FlashcardUserModel(user.AbstractUserModel):
-  def __init__(self, num_candidates, time_budget, slate_size, seed=0):
+  def __init__(self, num_candidates, time_budget, slate_size, seed=0, sample_seed=0):
     super(FlashcardUserModel, self).__init__(
         UserResponse, UserSampler(
             UserState, num_candidates, time_budget, 
-            seed=seed
+            seed=sample_seed
         ), slate_size)
     self.choice_model = MultinomialLogitChoiceModel({})
+    self._rng = np.random.RandomState(seed)
 
   def is_terminal(self):
     terminated = self._user_state._time > self._user_state._time_budget
@@ -52,7 +53,8 @@ class FlashcardUserModel(user.AbstractUserModel):
     doc_id = doc._doc_id
     W = self._user_state._W[doc_id]
     if not W.any(): # uninitialzed
-      self._user_state._W[doc_id] = W = doc.base_difficulty * np.random.uniform(0.5, 2.0, (1, 3)) # a uniform error for each user
+      error = self._user_state._doc_error[doc_id] # a uniform error for each user
+      self._user_state._W[doc_id] = W = doc.base_difficulty * error
       print(W)
     # use exponential function to simulate whether the user recalls
     last_review = self._user_state._time - self._user_state._last_review[doc_id]
@@ -60,6 +62,6 @@ class FlashcardUserModel(user.AbstractUserModel):
 
     pr = np.exp(-last_review / np.exp(np.dot(W, x))).squeeze()
     print(f"time: {self._user_state._time}, reviewing flashcard {doc_id}, recall rate = {pr}")
-    if np.random.rand() < pr: # remembered
+    if self._rng.random_sample() < pr: # remembered
       response._recall = True
     response._pr = pr
\ No newline at end of file
diff --git a/user/UserSampler.py b/user/UserSampler.py
index fc1613b..fa282dc 100644
--- a/user/UserSampler.py
+++ b/user/UserSampler.py
@@ -7,9 +7,13 @@ class UserSampler(user.AbstractUserSampler):
                num_candidates=10,
                time_budget=60,
                **kwargs):
-    self._state_parameters = {'num_candidates': num_candidates, 'time_budget': time_budget}
     super(UserSampler, self).__init__(user_ctor, **kwargs)
-
+    doc_error = self._rng.uniform(0.5, 1.5, (num_candidates, 3))
+    self._state_parameters = {
+      'num_candidates': num_candidates, 
+      'time_budget': time_budget,
+      'doc_error': doc_error
+    }
 
   def sample_user(self):
     return self._user_ctor(**self._state_parameters)
\ No newline at end of file
diff --git a/user/UserState.py b/user/UserState.py
index c253668..f554f65 100644
--- a/user/UserState.py
+++ b/user/UserState.py
@@ -3,13 +3,14 @@ import numpy as np
 from gym import spaces
 
 class UserState(user.AbstractUserState):
-  def __init__(self, num_candidates, time_budget):
+  def __init__(self, num_candidates, time_budget, doc_error):
     self._cards = num_candidates
     self._history = np.zeros((num_candidates, 3))
     self._last_review = np.repeat(-1.0, num_candidates)
     self._time_budget = time_budget
     self._time = 0
     self._W = np.zeros((num_candidates, 3))
+    self._doc_error = doc_error
     super(UserState, self).__init__()
   def create_observation(self):
     return {'history': self._history, 'last_review': self._last_review, 'time': self._time, 'time_budget': self._time_budget}