ISTQB Foundation Level learning objectives.

Learning objectives describe the level at which a candidate is expected to know or use a topic. ISTQB Foundation Level uses K1, K2, and K3 levels.

K-level overview

K1 means Remember, K2 means Understand, and K3 means Apply. K3 topics require applying a procedure to a familiar task, so they often need more practice than terms that only need recall.

K-levelMeaningWhat it asks you to doExample preparation
K1RememberRecognize or recall a term, fact, or basic ideaUse glossary review and short recall checks
K2UnderstandExplain, compare, classify, or interpret a conceptPractice explaining terms in your own words
K3ApplyUse a procedure in a familiar taskWork through examples such as selecting test cases from a technique

Depth varies by topic

Do not assume every syllabus topic has the same depth. A definition at K1 is different from a technique at K3. The learning objective level is one of the best signals for how to study a topic.