Designing a Great Product is Only Part of Usability
A large medical device manufacturer asked us to perform a human factors study on an autoinjector. During the study we observed some inversions where users would have injected their thumbs instead of the desired injection site if the device they were using had been real. This inversion stemmed from the cap and button both being the same color, making it difficult for patients to determine which end had the needle when referring to the Instructions for Use (IFU). The client knew this was a risk, however, it wasn't possible for them to change the cap or button colors at this point in the process.
While changing the device itself was off the table, changing the IFU was not. Our testing revealed that the graphic of the device in horizontal orientation in the IFU didn't do enough to show where the needle would come out because the cap and button are the same color. A new IFU was designed that showed the device in a vertical orientation, with the needle pointing down.
When Battelle conducted additional user studies after the IFU was redesigned, no inversions were observed. This IFU change allowed the product to be used more safely while saving the manufacturer the associated time and money with a project re-design.