The fourth book is way longer than the previous three, because there was a huge plot hole that Rowling had to cover up. It even led to the cutting of a character from the final story. On an official website, she states that the characters name was Mafalda. She also goes on to say that Mafalda was supposed to convey certain information about the Death Eaters to Harry, Ron and Hermione, because she's a nosy, eavesdropping Slytherin who likes to impress. She does not keep her mouth shut. Unfortunately, however bright she made her, there were obvious limitations to what an eleven-year-old at school could discover. Whereas Rita Skeeter whom she quickly built up to fulfill this function was much more flexible.

The first Harry Potter book was published in 1998 in the United States, the same year the final battle is fought. Rowling did say I open at the close.