As the names imply, closed won analysis looks at the deals that were successfully won by the sales team, while closed lost analysis looks at the deals that were not successfully won. Closed won analysis can give insight into the strategies that are working and which ones need to be improved. It can also help salespeople understand why they lost certain deals and how to avoid losing future deals. Closed lost analysis can be useful for understanding which products or services are not selling well and why. But since lost deals are often due to factors beyond the sales team's control and it isn't always as easy to gather customer feedback, closed won analysis is generally more helpful for understanding how to improve sales.