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Core Human Factors recently completed an injection pen study and came across an interesting phenomenon that stresses the importance of clearly conveying headings and illustrations in a product’s instructions for use (IFU). During this study, numerous users stated that they performed a certain step a particular way because of what they read in the heading and/or saw in the illustration; often users stated that they did not bother to read an instruction’s subtext. Only viewing an instruction’s heading and/or illustration can lead to product misuse and potential safety risks if the subtext contains additional important information on how to properly use the product.

The purpose of this formative study was to examine the usability of an injection pen and its accompanying IFU. Sixty-nine representative users participated in the study; some participants had experience with similar devices currently on the market, while others were inexperienced. The study took place in a room with a with a one-way mirror that was set up to look like a user’s living room, including a couch, rug, coffee table, and artwork. Although real needles were used (they attach to the top of the injection pen), participants were given an injection pad meant to mimic skin and told to strap the injection pad on their body where they would like to give the injection (e.g., abdomen, thigh).

Study sessions were 1-on-1 with a participant and moderator. Participants were told a fake prescription and handed the device and IFU; they were asked to use the product however they would in real life. After participants used the product the first time, they were asked to use the product again, this time following the IFU step-by-step, “reading a step and then doing a step, reading a step and then doing a step.” Inexperienced participants only were then trained, and came back within 5 days to perform the task a third time.

Participant performance was observed and all use errors and near misses were recorded. A use error (i.e., Incomplete/Incorrect) is defined as: an act or omission of an act that results in a different medical device response than intended by the manufacturer or expected by the user. A near miss (i.e., Resolved) is defined as: a use error that resolves. At the end of the session the Moderator probed the participant about every use error and near miss that occurred, with the intent of revealing the root cause (i.e., the underlying cause) for why the task was not completed correctly.

Several participants attributed their use errors to the fact that they did not read the full text for a particular instruction step, and instead only read the step’s heading or viewed the step’s illustration. Three specific examples of this occurring are provided below. Note that the specific wording of the IFU text in these examples was slightly altered to prevent privacy disclosure, however all efforts were made to keep the original intent of the content.

Example #1
The heading said, “Select a spot” but the subtext instructed users to select a spot AND clean the spot. As a result, several users did not clean the spot because they never saw the instruction to do so.

Furthermore, users reported not cleaning the spot because nothing in the step’s illustration indicated to them that they were supposed to clean the spot. This particular illustration showed two large images of the front and back of a person’s body with appropriate spots that could be selected highlighted in blue, as well as a relatively tiny circle at the top-right corner of the diagram that contained a small picture of 2 overlapping squares with the top square labeled “Alcohol.” The body images stood out to the user but they did not even notice the small alcohol swab pictures.

A potential fix for this problem could involve changing the heading to “Select a spot and clean it” or “Select and clean a spot.” In addition, the illustration could be altered to include

Example #2
The heading said, “Press and twist” but the subtext instructed users to screw the needle onto the device. As a result, some users attempted to just press the needle onto the device and give it a single twist, rather than pressing and screwing the needle onto the device until it was snugly attached.

Example #3
The heading said, “Testing” but the subtext instructed users to dial a test dose. As a result, some users did not dial a test dose and instead skipped right to dialing their prescribed dose.

Furthermore, users reported not dialing a test dose because nothing in the illustration specifically indicated that a test dose was being dialed; it appeared that a prescribed dose was being dialed. This particular illustration was identical to the illustration for the step about dialing your prescribed dose, and just showed the dial turned to a different amount (but prescribed dose amounts vary by person and the amount in the “testing” illustration may actually be a person’s prescribed amount).

To summarize, when reading a product’s instructions for use (i.e., quick guide), users may rely on just the heading and/or picture of an instructional step to know what to do. As such, headings and pictures need to be articulately worded and appropriately illustrated to convey all pertinent information, yet at the same time not overwhelm the user with too much information. Iteratively testing the headings and pictures for comprehension, especially without the accompanying subtext, can aid designers in creating instructions that lead to optimal performance and increased safety.

To cite: N Fink (2014, January 8). The Importance of Headings and Illustrations in Instructions [Blog Post].