At times, the student dashboard "Books Opened" and "Books Read" information may not match.
Book Open events are registered the first time students open a book. There is only one Book Open event per book, so time spent reading accumulates on the book until it is finished or abandoned (read to the last page, but the end button does not get pushed).
The reporting period chosen when pulling a report on books opened vs finished (read) plays a role in how the numbers appear. If the reporting period is 1/7/19 to 31/12/19 and the student had opened a book prior to 1/7/19 and then finishes it after 1/7/19, then the books opened could be less than the books finished.