Which type of usability testing focuses on identifying problems within a system so they can be resolved?

Formative usability testing is designed to identify and resolve usability problems within a system during the development process. This type of testing is iterative, meaning that it can take place multiple times as the product evolves. The main goal is to gather feedback early and often, enabling designers and developers to make necessary adjustments before the final implementation. This proactive approach helps in identifying issues related to navigation, comprehension, or interaction that users may encounter, which in turn improves the overall user experience.

In contrast, summative usability testing typically occurs after the product is developed to assess its effectiveness, rather than to uncover problems for resolution. A/B testing is used to compare two versions of a product to see which performs better, focusing on metrics rather than user problems. Exploratory testing allows users to interact with a system without a predetermined structure, which may uncover issues but is not specifically aimed at identifying and addressing usability problems systematically. Therefore, formative usability testing is the most relevant choice for the task of identifying and resolving issues within a system.