Malory Towers influenced Harry Potter

Rowling has spoken about growing up on British boarding school stories, and Hogwarts runs on Blyton's machinery before it runs on magic:

• Four houses, a points system, and a cup awarded at the end of the year
• A train that takes the children away from their parents in the first chapter
• Dormitory friendships formed in week one and kept for seven books
• A competitive sport nobody outside the school has heard of

The graph already holds Narnia and The Worst Witch pointing here. This is the third leg, and the one that supplies the institution rather than the wardrobe or the witch.