diff --git a/py/makecompresseddata.py b/py/makecompresseddata.py
index 28223a6d9c..9603de8713 100644
--- a/py/makecompresseddata.py
+++ b/py/makecompresseddata.py
@@ -51,9 +51,10 @@ def word_compression(error_strings):
             topn[word] += 1
 
     # Order not just by frequency, but by expected saving. i.e. prefer a longer string that is used less frequently.
+    # Use the word itself for ties so that compression is deterministic.
     def bytes_saved(item):
         w, n = item
-        return -((len(w) + 1) * (n - 1))
+        return -((len(w) + 1) * (n - 1)), w
 
     top128 = sorted(topn.items(), key=bytes_saved)[:128]
 
@@ -143,7 +144,7 @@ def ngram_compression(error_strings):
 
 
 def main(collected_path, fn):
-    error_strings = {}
+    error_strings = collections.OrderedDict()
     max_uncompressed_len = 0
     num_uses = 0