The time a student works in Holmwood's is measured as follows:

The time that is measured is the active working time. As soon as a student does not move their mouse for 10 seconds or more, time stops.

The time is only counted when an exercise is completed.

Reviewing answers and moving on to the next exercise wastes about 10-20% of the total time.

If you want to see how long a student has worked, you can find this here:

In the dashboard, go to Teaching> then click on the student's class and then on the student.
Then click on All Skills> clicking on the down arrow opens the overview of the times worked on the exercises.
You can also see how much time there is between the exercises.