Part 5: Cognitive Load: Do Not Make the Assessment Hard for the Wrong Reason

This is Part 5 of the 'Better Assessment Design Series:
Why Good Tests Are About More Than Questions and Scores.'
Click here for more in the series.

A good assessment should challenge people.

But it should challenge them for the right reason.

Sometimes assessments are difficult because the concept is genuinely complex. That is appropriate.

But sometimes assessments are difficult because the question is cluttered, wordy, confusing, poorly structured, or overloaded with irrelevant information.

That is a design problem.

Good assessment design is not about making assessments easy. It is about making sure the difficulty sits in the knowledge, skill or judgement being assessed, not in unnecessary confusion.

That is where cognitive load matters.

What cognitive load means

Cognitive load refers to the mental effort required to process information.

In assessment design, the goal is to make sure that mental effort goes into the thing being assessed.

It should not be wasted on:

• decoding confusing wording
• sorting through irrelevant detail
• comparing poorly written answer options
• navigating cluttered layouts
• remembering too much information at once
• trying to understand what the question is really asking

In simple terms:

An assessment should not be hard because it is messy.

It should be hard because the concept, task or decision is genuinely challenging.

Good difficulty and bad difficulty

Good difficulty comes from the intended capability.

For example:

• solving a problem
• applying a rule in context
• identifying relevant evidence
• comparing possible answers
• prioritising competing risks
• explaining a decision
• designing a solution

Bad difficulty comes from poor design.

For example:

• long sentences
• confusing wording
• irrelevant information
• double negatives
• cluttered layouts
• answer options that overlap
• too much information on one screen
• instructions that are far away from the task

Good difficulty helps measure capability.

Bad difficulty gets in the way of measurement.

The stop sign example

Consider this question:

While operating a vehicle in a school-adjacent pedestrian traffic zone under variable environmental conditions, what is the most appropriate response to a regulatory stop control device?

This is difficult to read.

A better version is:

You are driving near a school. It is raining and children are nearby. You see a stop sign. What should you do?

The second question is still meaningful. It includes context. It asks the person to apply judgement. But it removes unnecessary cognitive load.

The person can focus on the road safety decision, not on decoding the sentence.

Why cognitive load affects validity

When cognitive load is poorly managed, the assessment result becomes harder to interpret.

A person may choose the wrong answer not because they lack understanding, but because the question overloaded them.

That means the assessment may be measuring confusion as much as capability.

This is especially important in digital assessments, where people may be using different devices, screen sizes, internet speeds and testing environments.

It also matters in assessments with long scenarios, complex diagrams, detailed case studies or multiple steps.

Complexity is not automatically bad.

Unnecessary complexity is the problem.

Practical advice

When reviewing an assessment item, ask:

• Is all the information necessary?
• Is the scenario too long?
• Is the person being asked to remember too much at once?
• Are we testing one clear idea?
• Are the answer options easy to compare?
• Is the screen layout clean?
• Would an image, diagram, table or example help?
• Is the sequence of information logical?
• Are instructions clear and close to the task?
• Is attention being directed to the right information?

A useful principle is:

The effort should go into solving the problem, not understanding the question.

Good assessment design removes unnecessary friction.

It does not lower the standard.

It makes the assessment cleaner, fairer and more focused on what actually matters. 

Read the next article in the series.

Rudy Crous is a corporate psychologist and the co-founder and CEO of Compono, a people and culture platform that brings hiring, engagement, learning and credentialling together in one place, adding behavioural science to the processes most HR tools only track.