Page 96 - Making Instruction Work

chap 8 3/4/97 3:43 PM Page 82

82 making instruction work

Now, now, don’t get excited. You’ve made your point. You
noticed right off that the order in which things are taught can
make a big difference in how well (and how quickly) students
will reach mastery of the objectives. That’s exactly why the
hierarchy is so useful.
But there’s more. Sometimes the order in which things are
taught doesn’t matter, and that can be even more valuable to
know than where a specific learning sequence must be
imposed. When the learning difficulty isn’t impacted by the
order in which the skills are taught, you can safely leave the
sequencing decisions in the hands of your students (gasp!) so
that they can attack the one that’s best for them at the time.
Better yet, when some lessons require practice equipment,
and, for example, you don’t have enough atom-smashers to go
around, your hierarchy will tell you how each student can be
productively engaged while one is smashing a few atoms. So
the skill hierarchy is a useful tool.

What’s a Hierarchy?

A skill hierarchy is a picture that shows the prerequisite rela-
tionships between skills. It shows which are subordinate to
others; that is, which must be learned before others can use-
fully be attempted. It also shows which are independent of one
another; that is, which can be learned in any order. Just as the
task flowchart visualizes the key steps and decisions involved
in performance of a task, the hierarchy visualizes the relation-
ships between the skills needed in performance of a task.
The task analysis flowchart says, “This step is followed by
that step, which is followed by that decision, which is followed
by that step.” Thus, the flowchart describes a process.
In contrast, the hierarchy says, “This skill must be learned
before that one can be learned,” and “This objective is unrelat-
ed to that objective, and so these two objectives can be taught
in any order.” Thus, the hierarchy describes relationships.