The sense in sense: Revealing the role of human factors in medical adherence

Helping people to help themselves, Daniel Simmons, principal human factors consultant, CCD, reveals the role of human factors in medical adherence and how patients use their senses and make sense of things.

Ensuring patients take their medications at the right time, in the right quantities is a key challenge for device designers and manufacturers. Adherence levels remain stubbornly static at, on average, around 75%, and in some circumstances can fall as low as 25%.

While the reasons for low adherence are complex, one route to improvement is a better understanding of users, their needs and their behaviours. It was this reason that FDA regulations were created.

The 510(k) Human Factors Guidance requires that manufacturers make a systematic assessment of users, the conditions under which it will be used, how it will be used and whether it can be used safely. This provides a baseline, but improving adherence means ensuring that human factors are not just considered during development, but are central to the design and development process.

The aim is to make a device so intuitive that it becomes an integral part of users’ lives and their experience is more positive.

Aiming for intuitive

A device is intuitive when users understand it without reasoning, experimentation, assistance, or special training. This is a challenge when everyone has a different background, experience or expectations — what is intuitive to one person may not be to another.

This is where human factors’ practitioners bring a different dimension to the design process by suggesting a design approach that is based on human behaviour — how people live their lives and how a device can fit more easily into that.

With a new product, there is always a learning curve — the shorter the better. This can be achieved by reducing the amount of new information to be digested to reduce cognitive overload.

In processing information, our brains are subject to three types of demands, or loads; cognitive (including memory), visual and motor. Each demand requires a different amount of mental effort.

Trying to remember something or do a mental calculation requires the most mental effort. Users, therefore, tend to want to keep things as they are. As we use up mental effort, our attention span lapses. However, we also lose attention if too little mental effort is required.

We have a fundamental drive to seek out information, and this concept of cognitive load suggests that a medical product design that is too plain won’t hold our attention. A design that is too complex will overload us, and too much choice inhibits decision-making. A balance must be found.

Sensory importance

When we interact with any object, our first impression is visual — we see the object before the brain starts interpreting the visual stimuli. The importance of the visual system to medical products is in understanding that we make connections even when information is missing.

Considering instructions for use, how visual information is arranged and grouped will influence how the user interprets and understands the product and how easy or difficult it is to use. The same is true of touch, which has significant influence on our response to things, and designers can use tactile sensation to improve usability.

Designers must understand how users sense the world, how their brains interpret those sensations and how they think and act on what they perceive. Using this understanding, designers can provide cues that enable devices to be operated intuitively, confidently and safely.

Functionality is key — a device must work as intended, without question. The key to creating an intuitive medical product lies in aligning the design with the user’s mental model of similar objects and visual cues present on the device.

Mistakes will happen!

People will always make mistakes: it’s impossible to design a perfectly fail-safe system. Anticipating potential mistakes allows designers to design those mistakes out. Performing a failure modes and effects analysis (FMEA) can identify cognitive errors users could make.

These are part of the FDA’s design control regulations, but often they identify potential mechanical failures only. A human factors approach identifies cognitive errors from the users’ perspective to minimise potential error.

Positive reinforcement

People are motivated by progress, mastery and control. Small signs of progress can have a big effect. Providing feedback is especially important because it lets the user know they are progressing.

The closer we are to a goal, the more we focus on what’s remaining and this makes us more motivated. This creates a positive feedback loop. Users will be more engaged and this will promote a positive experience.

Understanding people enables medical product designers to develop products that are intuitive to use and that appeal to the target user population. Knowing how we sense and make sense of things — how we see, understand and decide — is the essence of good design.