Final answer:
To estimate the required retention rate, subtract the attrition rate from 100%.
Step-by-step explanation:
The required retention rate can be estimated using the formula:
Retention Rate = (1 - Attrition Rate)
The attrition rate can be found by subtracting the percentage of customers who stay with the loyalty/reward program from 100%.
For example, if 80% of customers stay with the program, the attrition rate would be 20%, and the required retention rate would be 80%.