Online Lecture

Virtually conducted lectures for a potentially big audience with input from one (or more) lecturers and limited interaction with participants due to the audience size.

Area of application

Online lectures are mostly applied in the university context but they can also be useful in any other situation where one main speaker wants to transmit content on a specific topic to a large group of participants. The goal is “one-way” knowledge sharing. Online lectures can be made available to groups of a hundred or more participants. They make sense starting from groups bigger than 40 participants. For smaller groups, more interactive formats such as classroom training or online seminar might be more appropriate.

This description focuses on “live” lectures where the participants join online at the time of lecture delivery. Lectures could also be produced offline and later uploaded online as an “on-demand” videos. Many of the same “lessons learnt” apply.



The level of possible interaction is relatively low and limited to a small number of participants, unless an additional tool is used such as a real-time survey, for example. Even then participants only have very limited possibilities to interact directly with the speaker during the lecture.

Virtual mode

The main advantage of online lectures is that many more participants from all over the world can attend at the same time. The main challenge is the fact that the lecturer receives very limited feedback from his/her audience.


The lecturers should avoid simply going over their presentation slides. It is recommended that they combine different methods and tools, for example, switching between showing their presentation and speaking directly to the audience with the camera on or including other activities such as:

  • Asking participants to watch a short video outside of the lecture (or if possible, showing it directly through the videoconference tool);
  • Doing a real-time survey;
  • Asking participants to read a short text which was sent via email;
  • Making participants click on a link shared through the chat where they can look at a web-application that fits the topic;
  • Using the chat for questions, remarks, comments.

The lecturers should also make sure to structure their talks appropriately (introduction, main part, summary), as they also would in an “offline lecture”.



It is recommended that the lecturers use their camera from time to time when lecturing rather than only showing the presentation screen all the time, and that they do not speak for long stretches of time.

Lecturers/facilitators should test beforehand whether the presentation works and if the slides can be viewed (ideally also on small screens, as participants might have better connections on their smartphones). They should also get familiar with the videoconferencing tool and its features in advance to be able to integrate some of the options in planning the lecture;

The lecturers should regularly ask for feedback from the participants through the chat and survey tools as well as leave time for Q&A in order to overcome the challenge of not having direct feedback from the audience and to keep them engaged and paying attention. Overall, they should not present too much content, focus the talk on a few key messages and make sure to explain them well. It is likely that less content can be communicated online than it would be possible for the same time in a physical lecture.




In order to ensure that the content of the lecture is appropriate and well geared towards the participants, preparation time is needed to conduct a needs assessment. The lecturer then needs enough time to prepare their presentation in detail, as they will not have time to reconsider parts during the lecture given that it is mostly a “one-(wo)man-show”.
If more than one lecturer speaks, tasks need to be defined clearly, e.g. using a moderation script.
In order to ensure engagement, the online lecture should not be too long.
The online lecture can be recorded for documentation purposes or for later use.



The costs are relatively low. Apart from the costs for an appropriate videoconferencing tool, the compensation of the lecturer(s) is the main cost factor. This includes their time for preparation and delivery, but also follow-up, e.g. answering follow-up questions by participants. If necessary, interpretation would also need to be budgeted.



From the videoconferencing tools available at PTB, a DFN or tixeo stream is most appropriate for a big group. Unfortunately, there might be issues with internet connections abroad, in which case other tools (in line with PTB regulations) might have to be considered.
The lecturer(s) need good connectivity and hardware (camera, microphone) and a quiet environment to ensure they can be understood well.



is an expert in the field covered in the lecture. He or she presents the content and transfers the knowledge. The lecturer is the main and likely only speaker and needs to prepare his or her talk in detail beforehand. Any information the lecturer wants to obtain about the audience needs to either be collected by a survey beforehand or through a real-time survey tool. An online lecture can also be held by more than one speaker, who split up the content between themselves.


Laura Haeussler

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