E-mail marketers use various metrics to assess the impact of their campaigns. Some of these metrics, like the ‘open rate’ (the number of opened emails), are focused on the effectiveness of the e-mails themselves.
Others, such as conversion and metrics that look at the impact of email marketing on the business, aim to show the contribution of email marketing to the bottom line. An example: the average order value per subscriber in case the mailing is intended to generate sales.
The last type of metrics and KPI’s require integration with other measurement systems such as web analytics applications. However, they are crucial because ultimately the aim of marketing is sales.