Customer Retention Rate calculates the proportion of customers in a particular period that are retained into the next period.

Transaction Recency measures the duration of time since a customer’s last purchase, indicating how recently repeat customers made previous purchases. It is a great way of measuring your business’s ability to bring back customers quickly and may vary based on industry and business model.

Lift in Spend is a loyalty metric that calculates the increased spend per customer or groups of customers across two periods.

Average Purchase Frequency counts the average number of transactions per customer per period. This metric is used to better understand customer behavior and purchase patterns.

Average Revenue Per User (ARPU) is a company's generated revenue that is averaged across all users and reported as a monthly or yearly value. ARPU is a top-level metric, that can easily be normalized and is often cited as a comparative measure between similar companies.