How do I measure the impact of frequency on engagement and unsubscribes?

• Frequency impact measurement requires both per-email and cumulative views:
• Per-email metrics:
• Open rate per email (does it decline with higher frequency?). Click rate per email. Revenue per email.
• Cumulative metrics over time:
• Total opens over the test period. Total clicks and conversions. Total revenue generated.
• Attrition metrics:
• Unsubscribe rate per email. Cumulative unsubscribes over time. Complaint rates. List decay rate.
• Long-term value:
• Subscriber lifetime value by frequency group. Retention rates over extended periods.

The tradeoff analysis: Higher frequency may generate more total revenue short-term but cause faster list decay. Model the long-term economics.

Frequency optimization balances short-term gain against long-term sustainability. Measure both to make informed decisions.