👓 How ‘Qi’ And ‘Za’ Changed Scrabble | FiveThirtyEight

The biggest change happened that same year, in March, when a new dictionary, the second edition of the Official Tournament and Club Word List, took effect. This edition christened QI and ZA as valid Scrabble words in North American play, along with FE, KI, OI and an additional 11,000-odd longer words. Two-letter words are the building blocks of Scrabble’s DNA, and the Q and Z are juicy high-point tiles — so the game evolved instantly.1 You can see that in the data set I created by scraping over 1.5 million tournament games covering the years 1973 to 2017 from cross-tables.com, an online clearinghouse for Scrabble tournament results. After the new dictionary hit the scene, the average score grew by about 10 points per player per game overnight. (The average score in the data set is about 374.)2