The Rule
Every campus lesson teaches exactly one thing. One skill, one concept, one ability. Not two related things. Not one thing with a bonus thing. Just one.
This sounds obvious. It is not. The temptation to add "just one more thing" to a lesson is constant, and I fall for it more often than I would like to admit.
What Happens With Two Things
I wrote a lesson once that tried to teach how to set up a tool and how to use one of its features. Two things. Both important. Both related. It seemed natural to put them together.
The result was a lesson that felt rushed in both halves. The setup section did not have enough detail because I was saving space for the feature section. The feature section assumed understanding from the setup section that the reader did not actually have yet.
Two topics, both under-taught. The reader finished the page knowing a little about two things instead of a lot about one thing. That is not learning. That is skimming.
Why One Thing Works
When a lesson has one focus, everything on the page supports that focus. The title tells you what you will learn. The introduction tells you why it matters. Every step moves you closer to being able to do that one thing. And at the end, you can do it.
There is no confusion about what the lesson was about. There is no "wait, which part was the main point?" There is just one thing, explained well, from start to finish.
The Test I Use
Before I finish a lesson, I try to summarize it in one sentence. "This lesson teaches you how to ___." If I cannot fill that blank with one clear action, the lesson is trying to do too much.
"This lesson teaches you how to check your usage" works. "This lesson teaches you how to check your usage and manage your account settings" does not. That is two lessons wearing one title.
More Lessons, Not Longer Lessons
The answer to "but there is more to teach" is never "add more to this lesson." The answer is "write another lesson." Two focused lessons will always teach more than one bloated lesson.
The campus skill tree has a lot of nodes in it. Each one is small. Each one does one thing. And together, they add up to something much bigger than any single lesson could be. That is the design. Not one long road, but many short steps. Each one clear. Each one complete.
