How to write instructions for use (IFU) to cater for different reading styles

30 Oct 2024 14min read

One important question to answer when designing effective instructions for use (IFU) is “how do your users read instructions?”. To help answer this question, we carried out some analysis from one of Team Consulting’s usability studies that evaluated a combination product. We focused on a task where lots of study participants made the same mistake, and we looked for patterns in how these participants read the instructions.  

What we found was interesting; and it matched our intuition (in our human factors group) based on thousands of simulated use study interviews. 

In summary, we identified four types of reader which I’ll describe in turn, along with some IFU design strategies for each. 

      1. The seagull
      2. The sloth
      3. The puppy
      4. The bee

1. The seagull

The seagull scans the entire instructions and briefly “dives down” into the first part of what they perceive to be the important sections – with more attention on the task steps. We can probably all relate to this strategy. If you have resorted to using instructions to answer a question, you may have scanned for relevant information, and when you think you have found the answer, you stop. Notice that I wrote “when you think you have found the answer”. This nuance is very important. We often see people fail tasks in a usability study because they think they know what to do, having only read the first sentence in a task step. This inevitably means they fail to read that all-important second or third sentence.

Team Consulting, types of IFU readers

Design strategy

There are two design suggestions for this type of reader.

The first is to streamline the entire IFU. In particular, shorten the task steps. The seagull is trying to complete the ‘IFU reading task’ quickly, so if you can create very short task steps, they might read every single word.

The second suggestion is to make important information stand out. This is harder than it sounds. Study participants often suggest we put important information in bold, or red, or underline it, but we know from experience that this rarely works. Instead, a better strategy is to create a clear information hierarchy. One step to achieving this is to categorise and prioritise the different types of information in the IFU and present those information types to the reader using consistently different visual styling. Take the example of warnings and task steps. The warning may be styled as white text on a black background, while the task steps may all have images and task numbers and be placed within thick border boxes. There might be other types of information to visually separate too. Core information – including the sort of pithy messages found in a quick reference guide – may be visually distinguished from detail, elaboration, or practical tips. The skill is then in creating an IFU where these information types are arranged in a simple, clean manner. Without a clear information hierarchy, the seagull makes up their own mind about what to read and what to ignore.

Key takeaway: Create a clear information hierarchy and, where possible, shorten the . When developing an IFU, it can be tempting to believe that everything is important, and everything must be read. But by accepting the reality that some users are seagulls, your best shot is to show them where the food is

Team Consulting design instructions for use for TympaHealth

2. The sloth

The sloth may read every word at the start, but as they work through the instructions, they become progressively less engaged. This is particularly noticeable with longer instructions. The speed that this reader turns pages gradually increases, to the point where they are almost flicking through the last few pages.

Team Consulting, types of IFU readers

They go through the tick-box process of ‘reading the IFU’, but may not understand it. These readers may be tired, they may have a short span of attention, or they may (subconsciously) allocate a chunk of time to the task of reading the IFU and so keep speeding up each time they realise they are running out of time. We’ve probably all been in meetings where the first agenda item is discussed in depth, and each successive item receives less attention than the last. The same can occur when reading instructions for use.

Design
strategy

The same design strategy that help the seagull will also help the sloth, although there are subtle differences, plus a third design suggestion.

A shorter IFU may allow the sloth to read the whole IFU properly. However, while the seagull may skip over background detail at the start of the IFU, the sloth typically starts at the beginning of the IFU and may run out of energy before reaching the task steps. As such, shortening the task steps may not be enough. You could streamline the background information too, but moving the task steps to the beginning may be more effective. Creating a clear information hierarchy, as suggested for the seagull, may or may not help – some sloths will always start at the beginning and read through in order. However, a clear information hierarchy won’t do any harm, and may help some, so is recommended.

The third design suggestion is to put important, and in particular counter-intuitive information, upfront in the instructions. This is particularly helpful if the errors being made by participants are due to users’ preconceptions. This may be because, for example, the device looks like other devices they have used, but works differently (this issue is all about mental models, which will be discussed later).

Key takeaway: Communicate critical messages early and, where possible, shorten the IFU. The sloth’s attention will gradually wane, and if you’re not careful, the IFU may put them to sleep before they get to the best bit.

3. The puppy

The puppy is similar to the sloth in that they start reading the IFU at the beginning, thoroughly. The difference is that the puppy, instead of a gradual attention decline, gives their full attention and then just stops, after only reading part of the instructions. This may be because they think they have reached the end of the relevant information. It may be because they think the IFU is not targeted at them. I recall one participant who followed this pattern: they explained to me that the instructions seemed to be stating the obvious, for example, keeping out of reach of children, checking for damage, not to use if it had been tampered with, checking the expiration date, etc. They therefore concluded that the IFU was designed for people with limited common sense and that they wouldn’t learn anything by reading it.

Team Consulting, types of IFU readers

Design strategy

The design strategies discussed previously will help the puppy as well. The most effective approach may be to start the instructions for use with the important information; this may be the task steps, or it may be a couple of key messages to overcome common use errors.

A clear information hierarchy can lead the puppy straight to the information that they want. For the participant example described above, a clear information hierarchy may have allowed them to skip over the “obvious information for people with limited common sense” and focus on the task steps.

While the puppy may love a short IFU, such an IFU is difficult to achieve in practice; there are often regulatory and risk-based drivers for including detail. Some users also appreciate additional information – the easiest way to keep everyone happy is to retain some detail but distinguish it from the core information with a clear information hierarchy.

Key takeaway: Communicate critical messages early and/or create a clear information hierarchy. You have a puppy’s full attention, but only for a short time, so use that window of opportunity wisely.

Team Consulting design instructions for use

4. The bee

The bee works hard and behaves perfectly in terms of engaging with the IFU. They read the whole IFU and seem to read it properly.

Team Consulting, types of IFU readers

Sometimes, we design studies where we direct participants to follow the IFU when attempting to operate a medical device. This is so we can fully test the instructions: are the pictures and text clear? Is anything confusing or ambiguous? Is the navigation clear? Is the IFU structure and order appropriate? Such studies are really helpful to design your IFU for the bee.

But why do these seemingly “perfect readers” make mistakes if they are reading the whole IFU? It usually comes down to the user’s preconception, or existing mental model. If users have experience with a similar device that works slightly differently, it can be very hard to shift their thinking (and associated assumptions) away from their existing mental model. Even bees can be tricked by “cheating flowers”.

There are classic examples of deeply ingrained mental models that we have seen time and time again. Inhaler users, for example, accustomed to their cap being just a dust cap, are thrown by a different inhaler where the cap has a function. I recall one participant getting utterly infuriated with the study inhaler IFU, exclaiming “why is it telling me to close the cap between inhalations when I don’t need to?!”. These existing mental models are so strong in users’ minds that the IFU needs to work really hard to counter these preconceptions. I have to confess to using a steroid inhaler for years before I realised I needed to ‘rinse and spit’. Having used a ‘blue puffer’ for many years, when I was prescribed a brown maintenance inhaler I assumed it was identical – just brown instead of blue. I even looked at the instructions, but not thoroughly enough to spot the extra step buried at the end. I only corrected my error when talking to a friend some years later.

Design strategy

Use steps can also be accompanied with rationale. For example, explaining that the device is different from others. This contradicts a previous design suggestion of shortening the IFU, so it’s important to make clear that it is a different type of information, only applicable to some readers. Achieving this once again involves creating a clear information hierarchy, which draws the reader to the information that is important to them.

Strong messaging early in the user’s journey might help, i.e. on the outside of the carton, on the inside of the carton lid, on a cardboard flap inside the carton, on the front of the folded IFU, or at the beginning of an unfolded IFU.

Mitigating errors by redesigning a static IFU may simply not work – we have seen examples where several approaches have been thoughtfully crafted, tested and refined and still not worked. Face-to-face training, or possibly digital animation-based training, may be the only way to counter a deeply ingrained mental model.

Key takeaway: Address ingrained mental models with strong messaging, preferably early on, and within a clear information hierarchy. Even the hard-working bee, who reads the entire IFU, can make mistakes, and it’s usually caused by their (incorrect) mental model.

What can we conclude?

There are a diverse range of readers who must be catered for when designing instructions. Luckily, as we consider each type of reader, we see a huge overlap in the design strategies we can employ.

Team Consulting, types of IFU readers

Clear information hierarchy

A clear information hierarchy is likely to help most readers (and for those readers that it doesn’t help, it will do no harm). The only caveat is that it can be quite difficult to create a clear information hierarchy. For example, if you were to just take an existing IFU design and create and apply design style rules to different information types, you could easily end up with a visual mess. The key to creating a clear information hierarchy is to consider design style rules alongside the IFU content, layout, navigation, ordering, form factor, paper folds and other key factors.

Streamlining the IFU

Shortening the IFU is a good aspiration, but in practice it is challenging. Some users will benefit from detail and rationale, and regulators will expect certain content to be included. However, do challenge every sentence and every word, especially those that are repetitive, negative, obvious or confusing. An IFU is not a script for controlling a machine, but a tool for optimising human behaviour.

Address ingrained mental models

Understanding the root cause of use issues is key to designing an effective IFU. In many cases, the root cause is an incorrect mental model. The best strategy may be to provide key information as early as possible in the user journey and/or explicitly call out differences between the device and similar devices. However, we know from experience that some preconceptions are too deep to overcome, no matter how well designed the information on the carton or the IFU. Only face-to-face training (or possibly digital animation-based instructions) can overcome what can only be described as a fundamental design flaw.

Test early, thoughtfully and frequently

Test your instructions for use with participants, but do so thoughtfully. A detailed IFU that performs well when directing participants to read it may give you false confidence. Such an IFU may perform well when used by the bee, but not when used by the seagull, sloth or puppy. Some stakeholders may be reluctant to change an IFU that performed well on a test (even if only tested with bees).

Answer fundamental IFU design questions early with focussed, little-and-often, testing. These tests can not only be enlightening, but they can also be cost-effective if study design elements are light-touch (e.g. protocol, IRB, participant group, location, environment, session length) – leave the process-shackles for late-stage confirmatory testing.

Closing thought

We need to accept that different people interact with instructions in different ways, and most will not read the entire IFU. When designing an IFU, we need to design for realistic IFU engagement by following a design process and design principles that caters for these differences. We must learn about the birds and the bees, as well as the sloths and the puppies.

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