diff --git a/R/data.R b/R/data.R
index 5aef7c2..6c5442e 100644
--- a/R/data.R
+++ b/R/data.R
@@ -212,6 +212,7 @@
 #' \item{domain}{Cognitive domain being measured. One of \code{"epmem"} for
 #' episodic memory, \code{"wmem"} for working memory and \code{"execfun"} for
 #' executive function/speed.}
+#' \item{timepoint}{Integer indicating the timepoint number.}
 #' \item{age}{Age of participant at the timepoint.}
 #' \item{test}{The particular test at this observation.}
 #' \item{y}{Response. For \code{"epmem"} and \code{"wmem"} this is the number
diff --git a/data-raw/lifespan.R b/data-raw/lifespan.R
index 22c8fe7..8142283 100644
--- a/data-raw/lifespan.R
+++ b/data-raw/lifespan.R
@@ -127,7 +127,7 @@ lifespan <- tibble(
     id = factor(id)
   ) %>%
   ungroup() %>%
-  select(-nu, -timepoint) %>%
+  select(-nu) %>%
   as.data.frame()
 
 mm <- model.matrix(~ 0 + domain, data = lifespan)
diff --git a/data/lifespan.rda b/data/lifespan.rda
index 5772425..d15e789 100644
Binary files a/data/lifespan.rda and b/data/lifespan.rda differ
diff --git a/man/lifespan.Rd b/man/lifespan.Rd
index 67b57d3..fbe5f7e 100644
--- a/man/lifespan.Rd
+++ b/man/lifespan.Rd
@@ -12,6 +12,7 @@
 \item{domain}{Cognitive domain being measured. One of \code{"epmem"} for
 episodic memory, \code{"wmem"} for working memory and \code{"execfun"} for
 executive function/speed.}
+\item{timepoint}{Integer indicating the timepoint number.}
 \item{age}{Age of participant at the timepoint.}
 \item{test}{The particular test at this observation.}
 \item{y}{Response. For \code{"epmem"} and \code{"wmem"} this is the number