  The online homework system WeBWorK has been successfully used at several
hundred colleges and universities. Despite its popularity, the WeBWorK system
does not provide detailed metrics of student performance to instructors. In
this article, we illustrate how an analysis of the log files of the WeBWorK
system can provide information such as the amount of time students spend on
WeBWorK assignments and how long they persist on problems. We estimate the time
spent on an assignment by combining log file events into sessions of student
activity. The validity of this method is confirmed by cross referencing with
another time estimate obtained from a learning management system. As an
application of these performance metrics, we contrast the behaviour of students
with WeBWorK scores less than 50% with the remainder of the class in a first
year Calculus course. This reveals that on average, the students who fail their
homework start their homework later, have shorter activity sessions, and are
less persistent when solving problems. We conclude by discussing the
implications of WeBWorK analytics for instructional practices and for the
future of learning analytics in undergraduate mathematics education.
