diff --git a/packages/perseus/src/renderer.tsx b/packages/perseus/src/renderer.tsx
index 7bb5e26a16..f605d30639 100644
--- a/packages/perseus/src/renderer.tsx
+++ b/packages/perseus/src/renderer.tsx
@@ -1595,7 +1595,10 @@ class Renderer
     };
 
     /**
-     * Returns an array of widget ids that are empty.
+     * Returns an array of widget ids that are empty (meaning widgets where the
+     * learner has not interacted with the widget yet or has not filled in all
+     * fields).  For example, the `interactive-graph` widget is considered
+     * empty if the graph is in the starting state.
      */
     emptyWidgets(): ReadonlyArray<string> {
         return emptyWidgetsFunctional(