I’m in the middle of the book now and while it’s clear from the research Posselt did that elite school origin does matter somewhat in admissions, I have yet to see any support for the statement that it’s one of the strongest predictors. Maybe it comes in later chapters.
As a side note, I just want to note that the passage about the Christian college student is very selectively quoted. Posselt gives a fuller description of the conversation in the book and it’s not quite as one-sided as it seems from the excerpts IHE quotes. They deliberately left out the quotes from faculty who had opposing views in the argument - yes, I know they spent one sentence noting it in the article, but it’s still weird that they selected around those statements when they were made in direct response to the really bad statements they did quote. For example, they did spend more time discussing the students’ background - but that was directly because of the college she attended, and it was actually brought up by the faculty defending her. They were trying to point out that her application was far more well-rounded than just the college she went to.
It wasn’t a shining moment of positivity for the academy, but still.