Attention is one of the most important factors in advertising effectiveness. This guide explores the science and economics behind advertising attention, from the difference between exposure and actual attention to the limitations of traditional testing methods. It looks at how attention can be measured and predicted, and how these insights can help marketers evaluate creative before a campaign goes live. By understanding what people notice and what makes an ad more engaging, marketers can make better creative decisions and create advertising that has a stronger chance of being noticed, remembered, and acted on.