The letter B in ASL The letter K in ASL The letter T in ASL

What is the word above?

Hint: It's what we're going to be learning about today!

You guessed:

You may have recognized the hand signals above as American Sign Language (ASL), but chances are, you probably didn’t know what specific letters they were. The process of spelling words using hand shapes in ASL is called fingerspelling.

Ready for the answer? Yes!

The letter B in ASL

This is a


The letter K in ASL

This is a


The letter T in ASL

This is a


This spells BKT, which stands for Bayesian Knowledge Tracing.

Don’t worry if you got it wrong, though. What do you think the chances are that someone who doesn’t know ASL would have guessed this word correctly by chance?

Drag the slider!

Pretty Small

Pretty Big

If you said pretty small, you’d be right.

So what does this have to do with Bayesian Knowledge Tracing? Well, BKT is an artificial intelligence algorithm that helps us predict what people know – often students, since BKT is typically used in educational contexts (e.g., Khan Academy and other online learning sites).

Like many algorithms, BKT relies on parameters to compute its output, which in this case is the probability that a student has learned a skill. Each parameter is essentially a probability (i.e., any number between 0 and 1, inclusive).

And guess what? You already know about the first parameter, P(guess), which is the probability that a student will answer correctly despite not knowing a skill.