One of the critical decisions you have to make when developing an elearning module is the length of the course.
In many cases the content of the course is what dictates the duration, but sometimes instructional designers are guilty of cramming too much content into a course.
So what is the ideal length of an online course?
First, consider how long you would want to spend taking an online course (without breaks). As a rule of thumb, the general theory is that people can only give about 20 minutes of attention before there is a need to take a “mental break”.
This doesn’t mean that your elearning courses should only be 20 minutes in length, but it does give you an idea of how you may wish to break-up the content. For example, lessons could be split into various topics so that the total length a learner is engaged with the content is no more than this amount of time. You could even consider splitting-up the content further with interactive components (games or quizzes).
If your course length is too long, then there is a strong possibility that the learner is going to seek ways to remove themselves from the course. To a certain extent this cannot be avoided, but you don’t want to encourage it either.
When I was creating an online course for a client, we made a point to keep lesson length to 20 minutes (maximum), and to create logical breaks in the content using interactions. The longest course was three hours.
In the beginning this was one course, but we ultimately decided to split the course into two sections of an hour and a half each. When people ask me today about online course length, my recommendation is to never exceed 1.5 hours of content. It just takes up too much time and you’re going to encourage the learner to go through the content quickly in the effort to just “get it over with”.
What’s nice about keeping courses to 1.5 hours maximum is that the course won’t suffer from a negative perception from the beginning (not many people want to sit for three hours straight at their computer – and almost no one can do this without many distractions).
In the end, your courses need to be as long as it takes for the content to be adequately delivered. Throughout course development, try to incorporate splits in the content in places that make sense so as to make the learning process a bit smoother.