ตามคำจำกัดความจากหนังสือ The Product Book: How to Become the Great Product Manager (2015) ได้อธิบายไว้ว่า
“A metric is a measurement of a task a customer does with your product. Collectively, your metrics can provide some great insight! From metrics, you might find an opportunity, such as wanting to get higher engagement with a component of your product.”