Collecting _____ is an important portion of testing a prototype in the test stage of design thinking.

The answer to your question is "Feedback". Collecting feedback is an important portion of testing a prototype in the test stage of design thinking. Here are the steps:

1. Prototype Creation: In the test stage of design thinking, the first step is to create a prototype. This is a scaled-down version of the product or feature.

2. User Testing: The next step is to have users interact with the prototype. This can be done in various ways, such as through user interviews, observations, and usability testing.

3. Collect Feedback: As users interact with the prototype, it's important to collect their feedback. This can be their initial reactions, thoughts, feelings, and any difficulties they encountered. This feedback is crucial as it provides insights into how the user interacts with the product and what improvements need to be made.

4. Analyze Feedback: After collecting feedback, the next step is to analyze it. Look for common themes or issues that multiple users experienced. This will help identify which areas of the prototype need improvement.

5. Iterate: Based on the feedback and its analysis, make the necessary changes to the prototype. This could be changing features, fixing bugs, or even starting from scratch in some cases.

6. Repeat: The process of testing and collecting feedback is often repeated multiple times until a satisfactory solution is reached. This iterative process is a key aspect of design thinking.