Custom certificate (plugin)

The criteria as as described on the plugin are as follows.

• Click: every time that a user access to a page in Moodle a log entry is stored.
• Session: set of two or more consecutive clicks in which the elapsed time between every pair of consecutive clicks does not overcome an established maximum time.
• Session duration: elapsed time between the first and the last click of the session.

I suspect this means the accuracy will depend significantly on the structure of the material in a course and also how students approach it. You might have students who have a habit of clicking on something then staring out the window for a few minutes, or huge blocks of text  and that would potentially make the results would vary significantly.