Due to time constraints, we utilized iterative concept testing through the prototyping phase rather than multiple rounds of formal usability testing. This helped us rapidly evolve our designs in each pass from wireframes to high fidelity.
This process also served as design-as-research, producing new findings. For instance, users needed information provided to them, but did not necessarily need help processing it. Originally we had a spatial sorting feature, but users found it confusing and unhelpful, and thus the feature was scrapped in favor of more familiar patterns.