Estimated rating for books that haven't been rated, based on the author's other books?

I’m reading まほり 上 Level 30?? , which hasn’t been graded by anyone else yet, and which is definitely harder than Level 30.

The same author also wrote 図書館の魔女 第一巻 Level 37, and, subjectively, I think that level 37 is probably a lot closer than level 30 for まほり as well.

This is an incredibly minor thing, but: does it make sense that the estimate for an ungraded book’s level should default to an average based on that same author’s graded books? It won’t always be correct - there are authors who write both for children and adults, and 森見 登美彦’s books go all the way from level 27 to level 42 - but most authors tend to be consistently right around the same level of difficulty.

That sounds like a reasonable idea.

At the same time, I feel like the system should really encourage people to have a good look at, say, the first few pages of something so that they can make a reasonable guess instead…

But your approach would help in cases where the user has really no clue (e.g., haven’t read it and no ebook available)