20 minute rule/guideline

Whenever something complex is presented where you need the students to really apply 'active learning' vs 'passive learning', you need to teach concepts within 20 minutes.  When you want the student's to be really attentive and actively engage with your materials, anything more than 20 minutes, will not be as effective.

In fact, this is why I think any video based trainings where the course creator talks for more than 20 minutes, is not effective and something that should be avoided almost always.  There are exceptions to this rule that I will explain a bit later, but for now, let's focus on this topic.

Regarding why this is really important, reflect back on all the technical trainings you've had, for example when you learned something technical on your own, based on hours of documentation reading and hours of video watching.  Did you learn the most by watching videos or by building something using that technology?

Almost all developers would agree that they learned more by building things than by watching hours and hours of videos.  If we know this is the case, why do course authors still keep creating hours and hours of videos?

For myself, I fall asleep easily and I hate boring long videos.  As a course creator, really do everything you can to teach concepts so easily so that you can do it under 20 minutes.  Then immediately have them move on to assignments so that they can really internalize the principles you've taught them.  Don't merely have them repeat what you showed in your video.  Really present concepts in a way so that in order for students to do the assignments, they have to really understand the key principles you've taught them.  Remember that students learn more through assignments than from videos, so shouldn't you spend equally more time carefully thinking about which assignments you should present in your course to really help students internalize key concepts?

A case study

Imagine another instructor comes to you and says there is no way they can follow this 20 minute rule.  What would you do?  Would you just agree with them?  Or would you look more deeply to see if really this is the case.

What I would do is have the instructor create an assignment landscape for the course.  Imagine, the instructor came back and they said their assignment landscape looks like this:

Key questions you should be asking here are:

  1. How long does it take for students to learn all the concepts needed for this learning unit?
  2. How long does it take for the students to do the assignment?  What % of them are able to complete successfully?  What % of them feel good about really understanding deeply the concepts that you've taught?  In other words, what % of the concepts were fully internalized into their beings?

If the answer to #1 is anything more than 20 minutes, I see issues.  If the answer to #2 is anything less than 95% of students successfully able to complete with no help, then something is wrong with the course.  If this assignment is a confidence destroyer rather a confidence booster, then something is also wrong. 

Often times, another issue is that the instructor may be thinking the assignment landscape looks like above, but often times, if you look at the assignment, it may really look like this:

In other words, maybe the reality is that the assignment #1 really only leverage four of the concepts taught and the other 5 concepts are either nice to knows or no need to knows and are not at all needed for that assignment.  if this is the case, you can also simplify the course by removing the must to knows, and introducing nice to knows later, once all the must to knows are first mastered.

Now, even if you did this, say that #1 is still super long and now it takes the instructor currently 2 hours to teach those concepts.  This is what I would do then.

1. I would challenge the instructor to figure out a way to teach better.  Maybe there is an analogy that can be used to shorten the learning curve.  Maybe there is a better way to explain things.  Maybe you can present the concept certain way, in certain order, to minimize confusion and to portray the concept in the most simple manner as possible.

2.  If there is absolutely no way to make the teaching any more concise, then instead of teaching 4 concepts in a row, teach one or two concepts at a time, followed by several assignments in between.  A good teacher can often teach several concepts in a very simple way that makes intuitive sense for the students.  A new teacher often needs a lot of practice and needs years of teaching experience to learn how to teach things simply and effectively.  If you're not a master teacher yet, continue to strive as no one is born as a master teacher and as it's just an art/craft that you can also master.  It just takes time.

Exceptions to the 20 minute rule

Any concepts that require serious brain power should follow the 20 minute rule. Topics that really are not that brain-intensive, especially if it's more of stories, and casual conversations, you could not follow the 20 minute rule.  The mode of learning that is engaged when difficult technical concepts are presented is what I call 'active learning'.  'passive learning' is like this course where you're not really engaging the left brain (the analytical mind) but where you're more listening to stories, examples, etc.  

There is another exception to the 20 minute rule.  Sometimes, I would do a demo or show a video recording of my demo to the students.  These demos are often long, sometimes over 60 or even 90 minutes.  In my demo, I try to show students each of my thought process.  Now, for these demo, I ONLY do them AFTER students had ample time to do the assignments themselves.  These demo are really helpful as what students did in say 5-20 hours, when they see how I do it in say 45 minutes or 60 minutes, they learn from my workflow (as they can compare my workflow with their workflow and see first hand how their workflow could be adjusted to save them time).  These type of demos, it's okay to have a video that's longer.   You should however, still be very careful on how many of these long demos you provide, as you don't want students to lean too heavily on you.  We need to help our students learn how to be self sufficient.  Therefore, showing them how we build things faster, could often lead to their confidence going down and where they become too reliant on you to provide answers.  That's a dangerous area and something you should avoid.  For me, I find that usually any long demos like this are ineffective if done more than once or twice a month (assuming students are going through the course full time spending 70-90 hours a week).

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