The document discusses analyzing marketing email campaign response data over a 3 day period to validate the "80-20 rule", where 80% of responses are received within the first 3 days. The analysis looked at campaign data from various business units like tickets, annual passes, lead generation, and accommodation. It was found that waiting more than 3 days captured very little additional response data. This validated that most response occurs within 3 days, allowing marketing to more quickly analyze campaign performance and determine if campaigns should be modified.