Learning Science · Accessibility, preferences and individual differences

Finding barriers to participation and understanding

Locate an obstacle in the route from accessing material to demonstrating understanding.

Use the examples to connect this lesson with the earlier topics. No specialist equipment is needed.

After reading, you can

Distinguish an access barrier from the target difficulty.
Investigate a barrier with the learner.

An unreadable graph

A graph encodes its two series only in red and green. A learner cannot reliably distinguish them and therefore cannot compare their trends. The task appears to reveal weak graph interpretation, but a design choice blocks the information needed for interpretation. Changing the distinction to include line patterns preserves the reasoning demand.

Trace the whole route

Access includes obtaining material, perceiving its information, navigating controls, understanding directions, responding and receiving feedback. A resource can be technically available yet unusable at one stage. An accessible document that leads to a keyboard-inoperable quiz leaves the learning route incomplete.

Ask what happens in the actual task and invite the learner’s account. Avoid inferring a diagnosis from a difficulty or demanding disclosure before addressing an obvious design barrier. Several learners may encounter the same barrier for different reasons. An improvement can be useful without assigning anyone to a fixed category.

Authored chart values for the accompanying access example. Series diverge after time 1; no causal effect is established.
Time (authored units)	Series A	Series B
0	5	5
1	6	6
2	8	6
3	10	7

Labels and patterns preserve the comparison

Authored values at times 0, 1, 2, 3: A is 5, 6, 8, 10; B is 5, 6, 6, 7. A is solid and directly labelled; B is dashed and directly labelled. Values first differ at time 2. Trends alone do not establish cause.

Preserve the important demand

Clarify the learning target, then distinguish essential complexity from avoidable obstacles. If the goal is comparing trends, readable labels and a data table can make the information available. If the goal includes interpreting a specific visual convention, teach that convention while providing access to its meaning.

CAST’s UDL Guidelines offer a framework for anticipating varied access and participation. They are design guidance, not a guarantee that every option benefits every learner. Use them to generate possible changes, then check the relevant route and outcome. Removing an obstacle should lead to a fairer opportunity to engage with the target, not an assumption that all remaining difficulty has disappeared.

Worked example

Repairing the graph task

How can the graph repair separate series identification from causal reasoning?

The teacher names each series directly, uses a solid and a dashed line, supplies a readable table and checks the display at the learner’s chosen magnification. The question still asks where the series diverge and whether a causal conclusion follows. The learner can now compare the information. If the causal inference remains wrong, the next teaching step addresses evidence and causation rather than visual access.
For the graph repair, ask the learner to identify a series before asking for an inference about its trend. This separates access to the encoded information from reasoning with it. If series identification still fails, revise labels or structure first. If identification succeeds and inference fails, preserve the access improvement while addressing the conceptual demand directly.

Direct labels, patterns, a table and a full description make series information available. Identifying a series still differs from making a justified causal inference.

Try it yourself

Think through each question before opening the answer.

Why might an accessible first page be insufficient?
Show the answer and reasoning
The learner must complete the whole route, including navigation, response and feedback.
A later blocked control can prevent participation.
Does removing a barrier guarantee mastery?
Show the answer and reasoning
No.
It makes relevant information or actions accessible. The learner may still need instruction and practice on the target itself.

What to carry forward

Locate the blocked stage in the actual task.
Improve access while retaining the essential learning demand.

References

Sources supporting the explanations and learning checks in this lesson.