Your student's course completion progress is calculated as a percentage of lessons they have completed.
Courses are broken down into a number of lessons. Each lesson is weighted equally towards the progress percentage.
In this example, the student has completed 2 lessons out of 5, meaning they have completed 40% of their course.
Drip Content Progress
The progress of students who are enrolled in drip content courses will take into consideration the entire course, not just the released drip lessons.
You had created a course with 40 lessons and are releasing 10 lessons by drip each week. After week 1, students who have completed all 10 lessons within week 1 will show their course progress as 25% as they have completed 10 out of 40 lessons.
More About Progress
Understanding Viewed and Completed Progress