At the end of last year, Joshua Lewis '06, a Scrabble enthusiast and postdoctoral scholar in the UC San Diego Cognitive Science Department, noted on his blog that since Scrabble was invented in 1938, the list of acceptable words for the game has changed, making some Scrabble tiles much easier to play. Invoking the ire of some, he developed a computer program, Valett, for determining letter valuations in word games based on statistical analyses of modern use.
"In addition to calculating the frequency of each letter in a corpus," explains Lewis, "Valett calculates the frequency by word length and the incoming and outgoing entropy for each letter's transition probabilities. One can then weight these properties of the corpus based on the structure of the game and arrive at a suggested value for each letter."
The game's inventor, Alfred Butts, based the original values and distribution of letters on the frequency of their appearance on the front page of The New York Times.
As analyzed by Valett, 14 letters change value. Among them, "Z" goes from 10 points to six, and an "X" from eight to five points. A few letters received a boost in scoring such as "U" which goes to two points and "G" which jumps to three.
The blog post soon had more than 10,000 hits, and Lewis was interviewed by a range of media including ABC News, NPR, BBC and Radio New Zealand. John Chew, the co-president of the North American Scrabble Association, called new valuations "catastrophic."
For more on the program and controversy, read this post from The Last Word, an independent Scrabble Tournament newsletter, which compiles Lewis' post with responses from Chew and Word Freak author Stefan Fatsis, and this BBC article.