diff --git a/numbers.qmd b/numbers.qmd
index 7e77bf5..cc233f9 100644
--- a/numbers.qmd
+++ b/numbers.qmd
@@ -488,7 +488,6 @@ lead(x)
     ```
 
 -   `x == lag(x)` tells you when the current value changes.
-    This is often useful combined with the grouping trick described in @sec-groups-from-logical.
 
     ```{r}
     x == lag(x)