diff --git a/russia-investigation/README.md b/russia-investigation/README.md
index 4005d83..47f41d7 100644
--- a/russia-investigation/README.md
+++ b/russia-investigation/README.md
@@ -2,6 +2,8 @@
 
 This folder contains data behind the story [Is The Russia Investigation Really Another Watergate?](https://projects.fivethirtyeight.com/russia-investigation/).
 
+`russia-investigation.csv` contains every special investigation since the Watergate probe began in 1973 and who was charged in them.
+
 Header | Definition
 ---|---------
 `investigation` | Unique id for each investigation