In Hawkes, the Mastery Level is the percentage of questions you must answer correctly to achieve mastery in Certify Mode. Once you have reached this level, you will be given credit for the lesson in your course.
The Mastery Level for each lesson set by your instructor, and is shown in the Certify box as shown below.
For example, if Certify has 20 questions assigned and the Mastery Level is set to 80%, you would need to get 16 of those questions correct to master the lesson.
The number of questions (or steps in the case of multiple step questions) you can get wrong are counted as "Strikes". In this example, you have four strikes total. If you exceed four strikes, you'll be placed out of Certify and have to start over.
Hawkes recommends spending ample time in Learn Mode and Practice Mode before moving to Certify Mode for each Lesson.