To measure and present the impact of your UI prototyping work, you need to use both quantitative and qualitative evidence. Quantitative evidence is the data and numbers that show the results and outcomes of your UI prototyping work. For example, you can use metrics such as conversion rates, retention rates, satisfaction scores, task completion rates, error rates, and time on task to show how your UI prototyping work improved the user interface performance and user behavior. Qualitative evidence is the feedback and insights that show the user perception and experience of your UI prototyping work. For example, you can use testimonials, reviews, ratings, comments, quotes, and case studies to show how your UI prototyping work met the user expectations and needs. By using both quantitative and qualitative evidence, you will be able to provide a balanced and credible assessment of the impact of your UI prototyping work.