Synchronous and Asynchronous Communication

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This page was originally authored by Byron Kask (2009)
Sarah Wood will revise for 2010!

All communication takes place either synchronously or asynchronously. Simply put, synchronous communication occurs in or near real-time. Examples of this include a spoken conversation that takes place face to face or over the phone, and a typed conversation using instant-messaging software. Conversely, asynchronous communication is not immediately received or responded to by those involved. Email, forum posts, mailed letters, and bulletin boards are examples of asynchronous communication. To confuse the issue, many technologies afford both types of communication. For instance, the talking on the phone would be considered synchronous communication, but if no one answers the phone, and a message is left, it would be asynchronous. Similarly, while email is a common asynchronous communication tool, some web-based email, such as Google's Gmail, include the ability to chat synchronously with another contact.


A soldier carries an early example (1945) of mobile synchronous radio communication.

Historically, synchronous communication was only available either in person with spoken word or within line of sight using signals. The telegraph and later the telephone extended distant synchronous communication beyond line of sight, but then limited all parties to locations that had wires that were physically connected. Radio communication began to remove the restrictions of place by allowing people to communicate from wherever they had the appropriate equipment to send and receive the signal. Radio equipment quickly became small enough that it was portable by a single person. Newer developments in synchronous communication are built on satellite, cell phone, and internet technologies.

Asynchronous communication developed when people were able to scratch out small pictographs or otherwise leave marks for others to find and understand. This type of communication has been refined with the creation of written language, and the formation of parchment and other writing surfaces. Until recently, communicating across great distances was only possible asynchronously, as messages were written and then carried to their recipients. Response time for this communication was dependant on the distance that needed to be traveled, and the conditions faced by the couriers. Furthermore, the messages could easily be lost or intercepted. The creation of modern postal systems improved the reliability greatly. New developments in storage media, remote access, and email enable by internet technology, allow reliable, timely, and accessible asynchronous communication.

Educational Relevance

Much of formal learning that takes place in both the classroom and online environment is assisted by the interactions between the student and the teacher, between students, and between the student and the course content (Anderson, 2004. Pullen & Snow, 2007). While delivery of content in a traditional classroom has not changed much in recent times with regards how the class communicates, the experience is now much different for distance education users.

When looking at online distance education, in general, synchronous communication works well for collaboration in very small groups, but is difficult to implement as a whole class. On the other hand, asynchronous communication can allow huge numbers of people to collaborate, but not necessarily in a timely manner. If the goal of distance education is to allow people to participate across varying locations and schedules, then asynchronous tools need to be the foundation upon which the classes are built. We see this with the Blackboard content management system (CMS) that the MET program uses. These systems allow students to fully articulate their views before posting them, and to respond to each other in depth. These systems are also not limited to the extension of a single thread, allowing diverse ideas and opinions to be compiled and discussed. Vonderwell, Liang, & Alderman (2007) found that this allowed students to check each other's understanding, help express new ideas, and develop new directions and ideas. Students using CMSs have expressed that it is enough for most of the coursework to be completed without additional synchronous communication (Ellis & Romano, 2008). However, as Tegn and Taveras (2005) noted, this gives rise to a the sense of isolation and disconnect. Synchronous communication largely addresses this issue, but it does not guarantee that we'll like who we meet.

Synchronous communication tools are very effective for smaller group interactions, but they can be problematic with more than a few people. My first time using the Wimba chat tool was chaotic. There were too many people discussing too many topics all at once without anyone addressing each other, which made unclear who the message was written to. The chat read like a giant dichotomous key that kept branching out exponentially. The voice chat was also out of control. As Lucas (1976) fictionally demonstrated, they had this problem a long time ago, in a galaxy far, far away too. Red Leader had to regulate communication to essential information only, telling Red Two to "cut the chatter." My experience using Elluminate was a little better with the audio, as only one person can talk at a time, but people (including me) would forget to end their turn. The point is that the tools that help build a sense of community can be painful to use with everyone present. Karabulut & Correia (2008) suggest that a good use for smaller-scale synchronous applications is for instructor's office hours, as there are only a few participants, and the feedback or answers can be received immediately.

Unfortunately, despite what some of the better CMSs offer, there seems to be no complete solution for both types of communication. Ghislandi, Mattei, Paolino, Pellegrini & Pisanu (2008) found that using a collection of different applications presented a problem with multiple logins and no synchronization between each component. This wiki, for example, requires a different login, and the content posted here is not reflected on our Blackboard site. However, it's the only tool for this course that allows asynchronous communication and collaboration between not only different sections of the course, but also those enrolled in different years.

Critique of Synchronous and Asynchronous Communication

A basic chat box allows quick communication, but with too many people can be frustrating.


Synchronous Pros

  • Instant communication - VOIP communication allows real conversation, and most chat apps show when the other users are typing.
  • Immediate feedback - Questions can be answered immediately, and problems can be worked through step-by-step, a process that could take days asynchronously.
  • In-person - There's a much more personable feel to using synchronous apps, especially if you can see and hear the other users.

Synchronous Cons

  • Requires guidelines - If more than two people are communicating at the same time, rules for successful dialog may be needed.
  • Lacks precision - People can usually express specific goals or needs better in writing than through a conversation, if the people are using distant communications (Singleton, 2007).
  • Exclusivity - Most voice-based synchronous tools accommodate only two or three people. Communication between individuals is difficult to share amongst a larger group (Singleton, 2007).
  • Lacks documentation - While many chat-based apps keep a record of the conversation, most audio and video conversations are do not.


All those red flags are messages I've ignored, a pitfall of asynchronous communication.

Asynchronous Pros

  • Communication can take place anytime - A recipient is not required for a message to be conveyed. By not required, I mean that they neither need to be available, nor need to be specified. Most threads in the forums, for instance, are not written with a specific recipient in mind.
  • Time to respond - Since no one is actively waiting, you can take time to craft and refine a good response.
  • Responses may be elaborate - Without the pressures of someone waiting, a message can be quite large. Conversely, chat boxes are usually small, and therefore do not display large messages well (Yes, I'm talking to you Wimba).
  • Manageable collaboration - It is helpful when working in groups to have the ability to post ideas, discuss, and edit over an extended period of time.

Asynchronous Cons

  • Communication may be missed or ignored - This is noticeable in the forums where posts have no replies.
  • Response time - Time between the message and response may be considerable, or not at all.
  • Impersonal - While longer typed messages do have the ability to show a user's personality, it is not conveyed as clearly as it is in video or voice communication.

Current Online Technologies

There are several categories of communication technologies, and so they are broken down as follows:

Name Categories Type of Communication Comments
Blackboard, WebCT CMS, Forum, Chat Mainly asynchronous Retail CMSs, cost prohibitive for most small institutions and individual instructors. See Course Management System and Common Elements and Limitations.
Elluminate CMS, Chat, VOIP, Video Synchronous and Asynchronous Features allow voice and video communication, but only one person may speak at a time. This generally works well, but people tend to forget to end their turn.
Facebook, Myspace, Nexopia SNS, Chat Synchronous and Asynchronous Web-based and platform independent. Often blocked or banned by school firewalls. See Social Network Site.
MediaWiki Wiki Asynchronous Free open-source. Requires an existing web server to run on, and access to a SQL database.
Moodle CMS, Forum, Chat Mainly asynchronous Free open-source. Requires an existing web server to run on, and access to a SQL database. See Course Management System and Common Elements and Limitations.
MSN/WLM, Yahoo Messenger Chat, VOIP, Video Synchronous Can message to email for asynchronous communication.
Skype VOIP, Video, Chat Synchronous See Using Skype to Increase Educational Communication. Free, but has paid features. Available across multiple platforms (Windows, MacOS, Linux, etc.), and can be run natively on several handheld devices.
Ventrillo, Teamspeak VOIP Synchronous Not peer to peer as it relies on an external server, so no one person hosts the conference. Often used in competitive or exclusive team-based gaming.


Anderson, T. (2004). Toward a theory of online learning. In T. Anderson & F. Elloumi (Eds.) Theory and Practice of Online Learning, 33-59. Retrieved Feb 11, 2009 from:

Attaran, M. (2007). Collaborative computing: a new management strategy for increasing productivity and building a better business. Business Strategy Series. Vol 8(8). p. 397-393.

Ellis, J. & Romano, D. (2008). Synchronous and Asynchronous Online Delivery: How Much Interaction in E-learning is Enough in Higher Education?. In G. Richards (Ed.), Proceedings of World Conference on E-Learning in Corporate, Government, Healthcare, and Higher Education 2008, 2615-2620.

Ghislandi, P., Mattei, A., Paolino, D., Pellegrini, A. & Pisanu, F. (2008). Designing Online Learning Communities for Higher Education: Possibilities and Limits of Moodle. In Proceedings of World Conference on Educational Multimedia, Hypermedia and Telecommunications 2008, 670-678.

Karabulut, A. & Correia, A. (2008). Skype, Elluminate, Adobe Connect, Ivisit: A comparison of Web-Based Video Conferencing Systems for Learning and Teaching. In K. McFerrin et al. (Eds.), Proceedings of Society for Information Technology and Teacher Education International Conference 2008, 481-484.

Pullen, M. J., and Snow, C. (2007) Integrating synchronous and asynchronous internet distributed education for maximum effectiveness. Education and Information Technologies, 12(3). Retreived Feb 22, 2009 from:

Singleton, A (2007) Warning: Synchronous communication tools can slow you down. Retrieved Feb 26, 2009 from:

Teng, T. and Taveras, M. (2005). Combining live video and audio broadcasting, synchronous chat, and asynchronous open forum discussion in distance education. Journal of Educational Technology Systems, 33(2), 121-129.

Vonderwell, S., Liang, X.; & Alderman, K. (2007) Asynchronous discussions and assessment in online learning. Journal of Research on Technology in Education, 39(3), 309-328.


Bourke-White, M. (1945) Us Fifth Army in Italy [image file] Retrieved Feb 20, 2009 from:

See Also

Guidelines for Developing Accessible Synchronous Communication and Collaboration Tools

How Synchronous Communication Helped Engage Our Community

Opinion: The Importance of Being Synchronous