diff --git a/NEWS.md b/NEWS.md
index 8693aea6..fe40940e 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,7 +1,7 @@
 # simstudy (development version)
 
 ## Breaking Changes
-* `trtAssign` with `ratio=Null` used to produce 0-index values but 1-indexed values if `ratio` was set. This was adjusted so now both versions produce 1-indexed values. This is a potentially breaking change for existsing scripts that use the generated treatment values while assuming the old behavior (e.g. using hardcoded values to filter).
+* `trtAssign` with `ratio=NULL` used to produce 0-index values but 1-indexed values if `ratio` was set. This was adjusted so now both versions produce 0-indexed values. This is a potentially breaking change for existing scripts that use the generated treatment values while assuming the old behavior (e.g. using hardcoded values to filter).
 
 ## New features
 * Function `logisticCoefs` determines the intercept and treatment/exposure