Caldecott study is worthwhile at all ages. I teach high ability LA students in K-8. This unit has:
1- a Caldecott scrapbook cover
2-a Caldecott evaluation sheet with lines and simpler questions for grades 1-3ish
3-a Caldecott evaluation sheet for older grades with more complex questions (grades 3-6)
You spend as long as you want on the unit as students fill in one sheet for each book they read on their own or you read together.