If there’s one trope of the mystery that stands out among all other types of stories—perhaps the single element that defines the mystery—it’s the solution being announced at the conclusion.

Almost all story leads the reader to a suspenseful ending. The mystery is unique in that the main character is responsible for explaining the prior events back to the reader in such a way as to make sense of them all. There are plenty of poorly-written books that open with a great dump of exposition to get the reader up to speed. Mystery has pretty much cornered the market on stories ending with an exposition dump.

This leads to mystery readers’ inevitable slaying of a story: “I knew who did it before I reached the end.” Usually this is put at some great insult or shut-down of the writer.

I’m going to go out on a limb and guess most mystery writers don’t cringe when a reader claims to have solved the whodunnnit before the last page. Why?

Magician Eric Mead describes a bit of inside baseball for his craft:

…if a magician shows somebody a trick and ninety percent of that trick fools them but there is a little ten percent sliver over here that does not fool them, the average person will say that the trick did not fool them even though they can’t explain ninety percent of it.

…if that same magician shows that same trick to his fellow conjurers, it only takes that ten percent sliver for them to admit that they were fooled.

The same could be said for mystery writers and their craft. The problem of penning a mystery novel isn’t managing to befuddle the reader to the point of utter despair before they reach the last page. If you want to experience such confusion, try Gertude Stein’s Blood on the Dining-Room Floor, a novella one reviewer notes “since it’s more or less impossible to work out who any of the characters are, up to and including the person whose blood is on the dining-room floor…then it can only be called a detective novel in the loosest sense conceivable.”

For almost every other mystery book written, fooling the reader is kind of a side quest for the novelist. Even in an Agatha Christie book where six shady suspects roam the English country house, the reader has a better than fifteen percent chance of simply guessing the murder by yanking a name from a hat. And when a reader claims to have deduced the murderer before the final chapter, I would ask in return, can you fully explain the who’s, what’s, where’s, and when’s of the crime? Or are you merely working on a hunch, one that may have to do with meta-analysis of the book? (“The writer keeps making this character seem innocent. I bet they’re the one.”) Or did you suspect the character at one point in the story, fleetingly, before moving on to other suspicions, and later told yourself you’d figured it out? Be honest here.

This is Eric Mead’s 90%, the part of the mystery other novelists don’t fret over when reading someone else’s work.

The 10% most readers overlook but keeps other novelists up at nights? Writing a novel that readers will pick up in the first place; writing a novel that will carry readers to the last page; filling pages with knockdown dialogue, tight scenes, and wonderful prose; and the perennial dream, writing a novel people are still talking about fifty years later. This is the sliver novelists concern themselves with when admiring (or critiquing) another mystery writer’s work. This 10% does require storytelling sleight of hand, and when it’s working it’s all-but-invisible to the reader.