In order to gain a comprehensive view of a competitor’s pricing, competitive shop programs often focus on a large number of items and numerous stores. This is due in part to the challenges mentioned above regarding data accuracy and reliability of the manual process. To increase reliability, retailers often increase labor by checking more items in more stores or increasing the frequency of checks. This is expensive. The top 10% of products sold typically represent 50% of the total sales dollars. Therefore, full book programs that invest as much in competitive shopping slow-moving items as in fast-moving products are not cost-effective.