When we launched the Visual Thesaurus Spelling Bee this past summer, we knew there was a built-in interest, but the response was still surprising. So far there have been 15,000 players who have tried their hand at spelling a grand total of 500,000 words. It’s clearly habit-forming, with many repeat visitors. The reason why it’s so addictive is that it’s been designed to be adaptive, so the more words that are spelled correctly, the more difficult the words become. And conversely, if you’re not a great speller, the words will get easier and easier. That way a player will always be quizzed at the appropriate skill level — from the orthographically challenged to the most expert spellers.
As more and more players try the Bee, the game has steadily improved based on data collected on how words are spelled. Words are being continuously reanalyzed for difficulty based on how spellers fare. Every five minutes, words are rescored for difficulty taking into account the latest data from the Bee spellers. That means there’s an increasingly better fit to different skill levels. …
For each word, a graph is generated to plot the distribution of right and wrong answers across different skill levels. Then a curve is drawn to fit the data. If that curve rises very steeply, then the word is a good “discriminator”: it’s an accurate way to separate the good spellers from the bad spellers.
I’ll give you a word of warning so you don’t stumble the way I did: be sure to read the definition on the lower right before trying to spell it.