Word Taxi - Frequently Asked Questions

How did you determined which words are most "useful"?
We used the open-source Scrabble program Quackle. We had the computer play against itself 60,000 times and then counted which words it played the most frequently.
Which dictionary do you use?
We use the OWL4, the official word list for competitive players in North America as of March 2019. You may notice that this list includes offensive words that are not included in the Hasbro dictionary.
How does your program work?
We generate short, 15-question quizzes. We show the most useful words first. As you learn these words, we will show you new words. Older words will be revisited using spaced repetition.
What is spaced repetition?
Spaced repetition is a scientific way to form long-term memories. When you guess a word correctly, we will show it to again in a few days. Guess it right again, and we will wait longer before showing it to you again, etc...
What's the best way to learn?
Try spending 10-20 minutes every day. Spaced repetition works best in short intervals over long periods of time.
What is WordScore?
WordScore is a measure of how well you know the Scrabble word list. A WordScore of 1,000,000 would mean that you know every single word played in our 60,000 game database. To calculate WordScore, we measure how well you know each word on a scale of 0 to 4. Then we multiply by each word's "usefulness", as measured by how often the computer played it. We also deduct points for guessing incorrect words.
How do you determine the percent of words I know?
This is simply WordScore / 10,000. More frequently-played words count more. For example, "QI" is the most frequently-played word in Scrabble. Knowing just this one word would mean you know 1.2% of the words played. On the other hand, "AARDVARK" only represents 0.000035% of the words played.