Attribution is the process of assigning credit for sales and conversions to touchpoints in conversion paths.
Attribution allows marketers to quantify each channel's contribution to sales and conversions. For example, many people may purchase on your site after searching for your brand on Google. However, they may have been introduced to your brand via a display ad or a blog. A marketer uses attribution to appropriately distribute monetary credit for purchases among the many marketing channels that may have contributed to each sale.