  Each time a learner in a self-paced online course seeks to answer an
assessment question, it takes some time for the student to read the question
and arrive at an answer to submit. If multiple attempts are allowed, and the
first answer is incorrect, it takes some time to provide a second answer. Here
we study the distribution of such "response times." We find that the log-normal
statistical model for such times, previously suggested in the literature, holds
for online courses. Users who, according to this model, tend to take longer on
submits are more likely to complete the course, have a higher level of
engagement, and achieve a higher grade. This finding can be the basis for
designing interventions in online courses, such as MOOCs, which would encourage
"fast" users to slow down.
