Asynchronous vs. Synchronous

By late summer/early fall 2020, I was regularly reading posts on social media from colleagues from around the country discussing their plans for teaching online for the then upcoming school year. I was puzzled by the number of faculty who said they were planning on teaching their online courses synchronously utilizing a video conferencing software such as Zoom. As someone who has been teaching one or two classes online almost every semester since 2005 and also as someone who has been studying and writing about distance education for the past ten years, the choice to teach online synchronously struck me as odd.

Prior to Covid and since the inception of the web and graphic browsers in the mid 1990s, almost all online courses at the college level have been taught asynchronously: that is, there is no set meeting time where all students and the instructor are together online simultaneously. Ron Legon's summary of a 2019 Changing Landscape of Online Education (CHOLE) study of 280 postsecondary institutions said that 84% of online courses are mainly or entirely asynchronous, and that percentage "rises to 92% for large online enrollment programs that recruit students nationally" (Legon, 2019). While some asynchronous courses have no interaction between students and no deadlines at all (other than the end of the semester when everything is due), most require students to regularly participate in the course and interact with other students. For example, students might be required to participate on a class discussion board, complete a small group assignment, a peer review activity, and so forth. But instead of completing class activities synchronously, these activities happen within a window of time spread out over a few days or once or twice a week.

While not everyone has experienced asynchronous learning, we all have had extensive experience with the synchronous mode of teaching because this is the mode of the traditional face-to-face classroom: students and instructors come together all at the same time and in the same place for some combination of lecture, discussion, group activities, and assessment. Synchronous teaching and learning are so thoroughly ingrained in all of us—from grade school through graduate school—that even the concept of a learning experience that does not take place synchronously can be hard to fully grasp. At the same time, the division between these modes can be murky. Face to face courses include assignments and homework that students need to complete outside of the set structure of the classroom meeting, and asynchronous online classes often include some real time discussions and interactions between students in small groups and the instructor—sometimes online, sometimes face to face.

There has been some previous research that suggests that the differences in learning outcomes between asynchronous versus synchronous online courses are either negligible or that asynchronous courses online are slightly more effective. Robert M. Bernard et al's 2004 study “How Does Distance Education Compare With Classroom Instruction? A Meta-Analysis of the Empirical Literature” analyzed studies from 1985 to 2002 comparing distance education courses taught asynchronously (including correspondence and very early online courses) and classroom courses taught synchronously. The study found both formats had their advantages and disadvantages, but the differences were small, and asynchronous courses were slightly more effective for Distance Education courses. M.D. Roblyer and colleagues' 2007 study "A Comparison of outcomes of virtual school courses offered in synchronous and asynchronous formats" found few differences between the formats as well. The one advantage synchronous online delivery had over asynchronous delivery was a modest increase in retention. Roblyer et al also agreed with Bernard et al in that the different levels of success among all online classes has more to do with successful course design that takes advantage of the affordances of the delivery mode than it has to do with the mode itself. I'd argue the same is true with traditional face to face courses as well: the determining factor of the success of those courses also depends on effective design of the course.

By "affordances," these scholars mean the strengths and weaknesses offered by different teaching mediums, and, in this case, the modes of asynchronous versus synchronous delivery. I believe the affordances of different teaching mediums and modes are frequently undervalued and, in addition to the previous research that supports this claim, my own experience has been that online courses are most effective as asynchronous offerings. I discuss this in some detail in my article "To Zoom or not to Zoom-- that is the question…" and also in my recent online and on-demand presentation at the 2022 CCCCs. But I have to say I think Sorel Reisman (2022) sums up my own negative impressions about Zoom toward the end of his article on the history of faculty reluctance to adjust their teaching to maximize the affordances of online courses: “Zoom doesn't require much curricular redesign. Teachers can essentially keep doing their quasi-Socratic, one-to-many lecture teaching the way they always have. In a nutshell, Zoom is the lazy person's way to teach online” (p. 75).

Reisman concludes that this "lazy person's" approach for online is not such a bad thing because even though it is far from his own ideals about how online learning should work, it is at least getting faculty to engage in online education. I disagree with Reisman on this score, though I must say my own strong preference for asynchronous online courses has softened a bit because of my own occasional use of Zoom during the pandemic for a small number of synchronous class sessions and student conferences, and also as a result of listening to my colleagues and survey participants who shared with me more details about their experiences teaching online during Covid. I will return to this point in the Discussion section of this website.

But again and as Means et al. (2014) said, "Some researchers found that learning interventions using asynchronous communication were more effective than those using synchronous communication, but interest in the topic has receded with the dominance of modern, Web-based learning systems that support both synchronous and asynchronous interactions" (p. 11).

Further, the reason why the great majority of online courses have for decades been almost entirely asynchronous is a simple matter of logistics: asynchronous classes are more flexible in terms of scheduling than synchronous ones, and this enables more students to attend college. Fundamentally, this has always been the goal of distance education and, prior to Covid, it was the primary reason why courses were offered online in the first place.

Ever since schools and colleges started offering correspondence courses in the U.S. in the late 19th century, the goal of distance education has been to extend access to higher education to nontraditional students who could not otherwise come to a college campus. Many of these students are attending college part-time, are returning to or just starting college several years after they completed high school, are still living at home, are working full-time and possibly supporting others while attending college, and so forth. The same was true 100 years ago: that is, most correspondence school students back then would be classified now as "nontraditional."

Physical distance has always played a role as well: correspondence courses then and online courses now make it possible for students to attend college and earn degrees from institutions thousands of miles away. But the more significant advantage of asynchronous online classes is the scheduling flexibility afforded by the format. This is why many traditional college students also take some asynchronous online classes online.

What was different during the Covid pandemic—particularly during the 2020-21 school year—was that the logic of offering online courses at all was flipped: sure, nontraditional students continued to take classes online, but the main audience for online classes during the 2020-21 school year were traditional students. That was even more true at institutions with few nontraditional students and thus (prior to Covid) few online courses. As I will discuss in more detail in both the Results and Discussion sections of this website, I think part of the motivation for many faculty for opting for synchronous online teaching was to attempt to more closely simulate the on-campus/in-class learning experience.