Evaluation of the Usability of the Immunization Information System in Brazil: A Mixed-Method Study.

Usability is a quality attribute that can evaluate the ease of use of user interfaces, based on standards called usability heuristics. To evaluate the usability components of the Brazilian Immunization Information System (IIS), focusing on the users and their interaction and agility with the interfaces. It was a concomitant and convergent mixed-method study that used a cross-sectional design for the quantitative approach and the indirect method of heuristic evaluation for the qualitative approach. Participants were 137 nursing professionals working in vaccination rooms, who completed a structured questionnaire on standards of usability quality, and 4 specialists in information technology, who used a semistructured form to carry out a software inspection. Descriptive and inferential statistics and the heuristic inspection were used for the analyses. The evaluation resulted in 10 violated heuristics and identified 14 usability problems on the 68 screens of the IIS. The system presented simple usability problems (grade 2 severity), which can be repaired, with a low correction priority. The heuristics best evaluated were error prevention (3.03 ± 0.54) and help and documentation (3.00 ± 0.68); and the worst evaluated was visibility of system status, with a mean of 2.62 ± 0.55. Professionals with a technical education level presented a higher score on the scales for the recognition rather than recall heuristic when compared with the nurses (2.77 ± 0.49 vs. 3.67 ± 0.66, p = 0.003). The system provides easy access for users, however, has weaknesses in its ability to allow the users to easily achieve their goals of interaction with the interface.