diff --git a/earwigbot/wiki/copyvios/workers.py b/earwigbot/wiki/copyvios/workers.py
index c056594..f143117 100644
--- a/earwigbot/wiki/copyvios/workers.py
+++ b/earwigbot/wiki/copyvios/workers.py
@@ -290,7 +290,7 @@ class CopyvioWorkspace(object):
 
         d_size = float(delta.size)
         return max(conf_with_article_and_delta(self._article.size, d_size),
-                   conf_with_delta(d_size), 0)
+                   conf_with_delta(d_size), 0.0)
 
     def _finish_early(self):
         """Finish handling links prematurely (if we've hit min_confidence)."""