diff --git a/spacy/syntax/ner.pxd b/spacy/syntax/ner.pxd
index 00ac8f6f8..3687bbb27 100644
--- a/spacy/syntax/ner.pxd
+++ b/spacy/syntax/ner.pxd
@@ -1,6 +1,7 @@
 from .transition_system cimport TransitionSystem
 from .transition_system cimport Transition
 from ._state cimport State
+from ..gold cimport GoldParseC
 
 
 cdef class BiluoPushDown(TransitionSystem):
diff --git a/spacy/syntax/ner.pyx b/spacy/syntax/ner.pyx
index 1787aaf27..8e9dcffe4 100644
--- a/spacy/syntax/ner.pyx
+++ b/spacy/syntax/ner.pyx
@@ -186,8 +186,13 @@ cdef class Begin:
 
     @staticmethod
     cdef int cost(const State* s, const GoldParseC* gold, int label) except -1:
+        if not Begin.is_valid(s, label):
+            return 9000
         cdef int g_act = gold.ner[s.i].move
         cdef int g_tag = gold.ner[s.i].label
+
+        if g_act == MISSING:
+            return 0
         if g_act == BEGIN:
             # B, Gold B --> Label match
             return label != g_tag
@@ -211,12 +216,17 @@ cdef class In:
 
     @staticmethod
     cdef int cost(const State* s, const GoldParseC* gold, int label) except -1:
+        if not In.is_valid(s, label):
+            return 9000
+        move = IN
         cdef int next_act = gold.ner[s.i+1].move if s.i < s.sent_len else OUT
         cdef int g_act = gold.ner[s.i].move
         cdef int g_tag = gold.ner[s.i].label
         cdef bint is_sunk = _entity_is_sunk(s, gold.ner)
-
-        if g_act == BEGIN:
+        
+        if g_act == MISSING:
+            return 0
+        elif g_act == BEGIN:
             # I, Gold B --> True (P of bad open entity sunk, R of this entity sunk)
             return 0
         elif g_act == IN:
@@ -231,6 +241,8 @@ cdef class In:
         elif g_act == UNIT:
             # I, Gold U --> True iff next tag == O
             return next_act != OUT
+        else:
+            return 1
 
 
 
@@ -248,10 +260,16 @@ cdef class Last:
 
     @staticmethod
     cdef int cost(const State* s, const GoldParseC* gold, int label) except -1:
+        if not Last.is_valid(s, label):
+            return 9000
+        move = LAST
+
         cdef int g_act = gold.ner[s.i].move
         cdef int g_tag = gold.ner[s.i].label
-
-        if g_act == BEGIN:
+        
+        if g_act == MISSING:
+            return 0
+        elif g_act == BEGIN:
             # L, Gold B --> True
             return 0
         elif g_act == IN:
@@ -266,6 +284,8 @@ cdef class Last:
         elif g_act == UNIT:
             # L, Gold U --> True
             return 0
+        else:
+            return 1
 
 
 cdef class Unit:
@@ -286,10 +306,14 @@ cdef class Unit:
 
     @staticmethod
     cdef int cost(const State* s, const GoldParseC* gold, int label) except -1:
+        if not Unit.is_valid(s, label):
+            return 9000
         cdef int g_act = gold.ner[s.i].move
         cdef int g_tag = gold.ner[s.i].label
 
-        if g_act == UNIT:
+        if g_act == MISSING:
+            return 0
+        elif g_act == UNIT:
             # U, Gold U --> True iff tag match
             return label != g_tag
         else:
@@ -312,10 +336,16 @@ cdef class Out:
     
     @staticmethod
     cdef int cost(const State* s, const GoldParseC* gold, int label) except -1:
+        if not Out.is_valid(s, label):
+            return 9000
+
         cdef int g_act = gold.ner[s.i].move
         cdef int g_tag = gold.ner[s.i].label
 
-        if g_act == BEGIN:
+
+        if g_act == MISSING:
+            return 0
+        elif g_act == BEGIN:
             # O, Gold B --> False
             return 1
         elif g_act == IN:
@@ -330,6 +360,93 @@ cdef class Out:
         elif g_act == UNIT:
             # O, Gold U --> False
             return 1
+        else:
+            return 1
+    
+"""
+
+# TODO: Move this logic into the cost functions
+cdef int _get_cost(int move, int label, const State* s, const GoldParseC* gold) except -1:
+    cdef bint is_sunk = _entity_is_sunk(s, gold.ner)
+    cdef int next_act = gold.ner[s.i+1].move if s.i < s.sent_len else OUT
+    cdef bint is_gold = _is_gold(move, label, gold.ner[s.i].move,
+                                gold.ner[s.i].label, next_act, is_sunk)
+    return not is_gold
+
+
+cdef bint _is_gold(int act, int tag, int g_act, int g_tag,
+                   int next_act, bint is_sunk):
+    if g_act == MISSING:
+        return True
+    if act == BEGIN:
+        if g_act == BEGIN:
+            # B, Gold B --> Label match
+            return tag == g_tag
+        else:
+            # B, Gold I --> False (P)
+            # B, Gold L --> False (P)
+            # B, Gold O --> False (P)
+            # B, Gold U --> False (P)
+            return False
+    elif act == IN:
+        if g_act == BEGIN:
+            # I, Gold B --> True (P of bad open entity sunk, R of this entity sunk)
+            return True
+        elif g_act == IN:
+            # I, Gold I --> True (label forced by prev, if mismatch, P and R both sunk)
+            return True
+        elif g_act == LAST:
+            # I, Gold L --> True iff this entity sunk and next tag == O
+            return is_sunk and (next_act == OUT or next_act == MISSING)
+        elif g_act == OUT:
+            # I, Gold O --> True iff next tag == O
+            return next_act == OUT or next_act == MISSING
+        elif g_act == UNIT:
+            # I, Gold U --> True iff next tag == O
+            return next_act == OUT
+    elif act == LAST:
+        if g_act == BEGIN:
+            # L, Gold B --> True
+            return True
+        elif g_act == IN:
+            # L, Gold I --> True iff this entity sunk
+            return is_sunk
+        elif g_act == LAST:
+            # L, Gold L --> True
+            return True
+        elif g_act == OUT:
+            # L, Gold O --> True
+            return True
+        elif g_act == UNIT:
+            # L, Gold U --> True
+            return True
+    elif act == OUT:
+        if g_act == BEGIN:
+            # O, Gold B --> False
+            return False
+        elif g_act == IN:
+            # O, Gold I --> True
+            return True
+        elif g_act == LAST:
+            # O, Gold L --> True
+            return True
+        elif g_act == OUT:
+            # O, Gold O --> True
+            return True
+        elif g_act == UNIT:
+            # O, Gold U --> False
+            return False
+    elif act == UNIT:
+        if g_act == UNIT:
+            # U, Gold U --> True iff tag match
+            return tag == g_tag
+        else:
+            # U, Gold B --> False
+            # U, Gold I --> False
+            # U, Gold L --> False
+            # U, Gold O --> False
+            return False
+"""
 
 
 class OracleError(Exception):