I told the authors that they could make it a Show HN after they explained it's part of a project they've been working on for months, which included an exhaustive literature review. That's a lot more work than a garden-variety blog post or article, and the intention behind Show HN has always been to let people share their work.

So while you're definitely right that by default a Show HN needs to be more than just an article, in this case it's a borderline call that we let through. HN is a spirit-of-the-law kind of place.

Edit: I forgot to mention, and don't see it elsewhere on the page, that 80,000 Hours is a YC S15 nonprofit. Sorry; should have made that clear.