Usability of an Insulin Injection Educational Tool Across Nursing Experience Levels: An Explanatory Sequential Mixed-Methods Study

In hospital wards dedicated to treating diabetes, nurses spend a significant portion of their day teaching patients how to inject insulin. This is not merely a matter of handing over a needle; it is a critical lesson where a small mistake in technique can lead to dangerous swings in blood sugar levels. To help, many hospitals provide standardized teaching kits—portable boxes containing visual aids, checklists, and digital links to guide the process. The assumption behind these tools is that a well-designed kit will work equally well for everyone, regardless of who is holding it. However, the reality of human learning is more complex. A nurse who has been practicing for decades possesses a different kind of knowledge than a nurse in their first few months on the job. The former has internalized the steps until they are automatic, while the latter is still building the mental map required to perform the task safely. Understanding how these different levels of experience interact with the same teaching tool is essential, because a kit that feels like a helpful guide to one person might feel like a confusing obstacle to another.

A team of researchers at a major hospital in China set out to investigate exactly this dynamic. They wanted to know if a specific insulin injection teaching kit was perceived as equally useful by nurses at different stages of their careers. To do this, they gathered twenty-six nurses from an endocrinology ward and divided them into three groups based on their experience: interns with less than six months of practice, junior nurses with one to seven years of experience, and senior nurses with more than seven years of experience. Each nurse used the physical teaching kit for at least a week. The kit itself was a standardized box containing a practice pad with synthetic skin for needle angle training, a panel of QR codes linking to instructional videos, and a checklist of the seven steps required for a safe injection. After using the kit, the nurses rated its usability on a standard scale from zero to one hundred, where higher scores indicate a tool that is easier and more pleasant to use. Following the ratings, the researchers interviewed the nurses to understand the stories behind their scores.

The results revealed a clear, though nuanced, divide in how the tool was experienced. When the researchers looked at the average scores, the junior nurses gave the highest ratings, with a median score of 92.5. The senior nurses scored the tool slightly lower at 87.5, and the interns gave it the lowest median score of 75.0. While the difference between the junior nurses and the interns was notable, the statistical analysis suggested that the pattern of scores did not follow a simple straight line where more experience always meant a better or worse rating. Instead, the data pointed to a more complex relationship where the tool fit the needs of the junior nurses perfectly, but created friction for the other two groups. The junior nurses described the kit as a seamless part of their workflow, a complete system they could grab and use immediately without hesitation. They felt the organization of the materials helped them teach patients efficiently.

In contrast, the interns and senior nurses found different kinds of problems, even though their overall scores were lower than the junior group. The interns reported that the kit was difficult to use on their own. They felt they needed a teacher to walk them through the materials first before they could use the kit independently. For them, the sheer amount of information was overwhelming, and they lacked the foundational knowledge to navigate the checklist and videos without guidance. On the other end of the spectrum, the senior nurses offered a split perspective. About half of them rated the kit highly, but the other half found it frustrating. Those who were frustrated described the kit as cluttered and redundant. They explained that because they already knew the procedure by heart, the constant need to scan QR codes and look up information on the checklist slowed them down. For an expert, these extra steps felt like unnecessary interruptions to a process that should be automatic.

The researchers identified three specific areas where the design of the kit failed to match the user's experience level. First, there was a lack of introductory guidance for beginners, leaving interns unsure of how to start. Second, the visual layout was too crowded, with too many codes and materials placed close together, making it hard to find what was needed quickly. Third, the physical arrangement of the items inside the box was compact and disorganized, causing nurses to fumble when they needed to grab multiple items at once. The study suggests that the problem was not that the kit was bad, but that it was designed as a single solution for three very different types of users. A tool that provides the right amount of structure for a novice can feel like a burden to an expert, while a tool that is streamlined for an expert can leave a novice lost.

Ultimately, the study concludes that simply averaging the scores of all users together can hide these important differences. If a hospital only looked at the overall average, they might think the kit was universally successful, missing the fact that it was actually failing to support the interns and frustrating the experts. The researchers propose that future evaluations of such tools should look at different experience levels separately. They suggest that the best design might not be a single kit for everyone, but rather an adaptable system that offers a guided, step-by-step path for beginners and a streamlined, fast-track view for experts. By recognizing that the "fit" between a person and a tool depends on their experience, healthcare educators can create resources that truly support nurses at every stage of their career, ensuring that the patients they teach receive the safest and most effective care.