diff --git a/src/variable.cpp b/src/variable.cpp
index c9051de9ad..1981d000c3 100644
--- a/src/variable.cpp
+++ b/src/variable.cpp
@@ -3775,7 +3775,7 @@ int Variable::group_function(char *word, char *contents, Tree **tree,
 
   // match word to group function
 
-  double value;
+  double value = 0.0;
 
   if (strcmp(word,"count") == 0) {
     if (narg == 1) value = group->count(igroup);