In judo class they kinda do the same thing every time: you warm up and then work on different moves. Different moves in different classes, and there are different levels, but within any level the classes don’t really have a sequence. You just start where you start, practice over and over, and gradually improve. Different students in the class are at different levels, both when it comes to specific judo expertise and also general strength, endurance, and flexibility, so it wouldn’t make sense to set up the class sequentially. Even during the semester, some people show up at the dojo once a week, others twice or three times a week.
Now compare that with how we organize our statistics classes. Each course has a sequence, everyone starts on week 1 and ends on week 15 (or less for a short course), and the assumption is that everyone starts at the same level, has the same abilities, will put in the same level of effort, and can learn at the same pace. We know this isn’t so, and we try our best to adapt to the levels of all the students in the class, but the baseline is uniformity.
The main way in which we adapt to different levels of students is to offer many different courses, so each student can jump in at his or her own level. But this still doesn’t account for different abilities, different amounts of time spent during the semester, and so forth.
Also, and relatedly, I don’t think the sequential model works so well within a course, even setting aside the differences between students. There is typically only a weak ordering of the different topics within a statistics course, and to really learn the material you have to keep going back and practicing what you’ve learned.
The sequential model works well in a textbook—it’s good to be able to find what you need, and see how it relates to the other material you’ll be learning. But in a course, I’m thinking we’d be better off moving toward the judo model, in which we have a bunch of classes with regular hours and students can drop in and practice, setting their schedules as they see fit. We could then assess progress using standardized tests instead of course grades.
P.S. I’m not an expert on judo, so please take the above description as approximate. This post is really about statistics teaching, not judo.