To measure the impact of sticker branding, you need to define metrics and methods such as reach and exposure, response and feedback, conversion and retention, as well as satisfaction and loyalty. Reach and exposure can be measured by counting the number of people who see your stickers on a layout or surface, or receive them as giveaways or rewards. Response and feedback can be gauged by observing reactions to your stickers on a layout or surface, as well as comments, likes, shares, or reviews online or offline. Conversion and retention can be evaluated by tracking how many people take action after seeing your stickers on a layout or surface, such as buying, subscribing, donating, or referring your brand. Lastly, satisfaction and loyalty can be assessed by determining how many people are happy with your stickers on a layout or surface, and become repeat customers, advocates, or fans of your brand.