Figure 8 displays one of the many ways in which open online course registration differs from conventional models. Although most registrants enroll before the launch of the course, there is considerable variability across courses, driven in large part by variation in preregistration windows. Table 5 shows the percentages of registrants who register before course launch, during the course, and after the course closes and certification is generally not a possibility. Many of these latter percentages are small only because the course closing date was close to our data collection horizon of September 8, 2013. Many of these courses remain open to registrants but closed for certification, which means that course certification percentages will continue to decline over time. This is another demonstration of the short-sighted, misleading nature of certification percentages as evaluation metrics.

Figure 8. Distribution of enrollment dates in days relative to course launch, for all registrants by course. Median registration day for certificate earners is shown as a hollow diamond. Box borders are the 25th and 75th percentiles. Whiskers terminate at the 5th and 95th percentiles.

Figure 8

Table 5. Enrollment distributions and related statistics showing wide variation in enrollment times relative to course windows.

Table 5

Figure 8 also illustrates that there are small differences in the median registration times between certificate earners and registrants overall. Figure 9 shows overall enrollment, average view rates, explore rates, and certification rates, all referenced to the launch date of courses, across all HarvardX and MITx offerings. The likelihood of certification as well as exploration is highest for registrants enrolling near the launch date. The enrollment pattern also shows overall acceleration in registration in the weeks closest to launch dates, although these vary across courses. In contrast, viewing likelihood is stable after course launch dates. This suggests that exploration and certification benefits from synchronous course schedules and the cohorts that they build. Managing asynchronicity to maintain registrant involvement regardless of enrollment date is an ongoing challenge for instructors and a fertile area for future research.

Figure 9. Enrollment by week relative to launch (above), with the percentage of registrants who ultimately view, explore, and are certified, across all HarvardX and MITx courses (below).

Figure 9