The Iron Rule of RFM

2. Quantity of lifetime purchases (to measure frequency).

3. Total lifetime dollar sales (to measure monetary value.) Actually some catalogers prefer to use only total sales during the last 12 months for this measure, but they are in the minority.

For example, if we looked up John Doe in our master customer file, we might find (among other data) these three pieces of data (separated here by commas and enclosed by double quotes):