Etta James died recently. To most people that meant the loss of a blues legend, but for crossword puzzle writers like myself, it meant something quite different. Etta James was famous in real life, but she’s also “crossword-famous”—a woman whose handy, four-letter first name has gotten us out of many tough corners and spared us countless painful rewrites.

What does it mean to be crossword-famous? That your name is better known by regular crossword-solvers than it is by the general population. Take a guy like Jay Leno—his last name is a godsend to puzzle writers, and it appears in crosswords all the time. But Leno is also a television megastar, known to people who have never lingered with a pen over the back page of the New York Times. He’s no more crossword-famous than he is real-famous.

With this in mind, Slate has created an objective measure of crossword fame, calculated by dividing the number of times a person’s name has appeared as a clue in the New York Times crossword puzzle by the number of times that same person’s name has appeared in the rest of the newspaper combined. In honor of Times puzzle editor Will Shortz, we have dubbed this new statistic the Shortz Factor. For each name, we’ve compared its frequencies in the Times crossword and the paper’s other sections going all the way back to 1993, when Shortz took over from his predecessor, Eugene T. Maleska. For example, ETTA, as in Etta James, has turned up 80 times in the puzzle during that span, while “Etta James” showed up 198 times in the rest of the paper. Divide one by the other and you get her Shortz Factor: 0.40. That means the legendary blues singer is less than half as famous in the crossword puzzle as she was in real life.

Before we get to our crossword hall of fame, let’s consider the specific qualities that might turn a minor celebrity into a crossword icon. The applicant must satisfy three criteria:

i. He or she must have a name that’s useful for crosswords. Puzzle writers prefer having rare letters in unusual combinations (for example, I once snuck JFK, JR into a New York Times crossword at 1-down), but short groupings of common letters are the lifeblood of crosswords, and you’ll need a lot of them if you want to make things work. For that reason, crossword-famous names are likely to be three, four, or five letters long, with as many 1-point Scrabble letters as possible. Think of names with a lot of vowels, and any combination of N, R, T, L, or S.

ii. His or her name must be unusual. If it’s not, there will be too many alternative paths to the same puzzle outcome. LEE is a useful and common crossword entry, for instance, but there are dozens of famous LEEs out there; someone like Spike or Ang isn’t going to get as much clue love if he’s competing with Bruce, Brenda, and Sara. Other useful names that won’t produce any singular crossword celebrities include LOU, ANNA, ELI, and ALAN. An ambiguous name like ART would be even worse, since it can also be clued as a regular word. The more unfamiliar the name, the better.

iii. He or she can’t be too famous. Muhammad ALI has been name-checked more often than anyone else (173 times) in the New York Times crossword since 1993, but he’s also arguably the most recognizable athlete of all time, so his fame transcends the lettered grid. Indeed, his name has shown up in the rest of the newspaper 1,927 times, so his Shortz Factor is 0.09—less than one-quarter of Etta James’. (Shortz Factors for rival ALIs, including his daughter Laila and actress ALI MacGraw, wouldn’t be much higher.) Next on the list of mentions in Times crosswords are Arthur ASHE (146 puzzle mentions) and Yoko ONO (144). These well-known figures were mentioned 1,323 and 776 times in the rest of the newspaper, respectively, and their Shortz Factors are just 0.11 and 0.18.

A word on methodology: Our 18-year window gives us about 6,600 crosswords to look at, and well over half a million clues. To have a valid Shortz Factor, a name must appear at least 25 times in the puzzle during that stretch. (Otherwise a real nobody could walk off with the trophy by getting, say, six puzzle mentions and one paper mention, and no one would like that.)

So who are the most crossword-famous people in the world? Our analysis found exactly seven celebrities with a Shortz Factor greater than 1.00. These form the select group of crossword icons whose names appear more often in the puzzle than they do in the newspaper of record. In reverse order of fame, we hereby present the first-ever Shortz List of Crossword Celebrities: