Definition
An email metrics hierarchy organises the many available email metrics into tiers based on their strategic significance and the decisions they support. The hierarchy typically has three to four levels, ranging from operational metrics (sends, deliveries) at the base, through engagement metrics (opens, clicks) in the middle, to business outcome metrics (revenue, ROI, profit) at the top. The hierarchy ensures that reporting focuses on metrics that matter most while not ignoring the operational foundations that support them.
Typical Hierarchy
- Tier 1 — Business outcomes: Revenue attributed, ROI, profit, subscriber equity, channel contribution
- Tier 2 — Programme health: Engagement rate, list growth, churn rate, deliverability score, conversion rate
- Tier 3 — Campaign performance: Open rate, click rate, conversion rate, bounce rate, complaint rate
- Tier 4 — Operational: Sends, deliveries, queue times, API response rates, template rendering
Best Practices
- Use the hierarchy to structure reporting dashboards so each audience sees metrics at their level
- Ensure each metric at lower tiers can be traced upward to its impact on higher-tier metrics
- Review the hierarchy annually as programme maturity and business priorities evolve
- Limit executive reporting to Tier 1 and Tier 2 metrics; operational teams need all tiers
- Use the hierarchy to identify gaps — if a Tier 1 metric cannot be calculated, build the necessary foundation first
Related Glossary Terms
Abandoned Cart Email
An abandoned cart email is an automated message sent to customers who added items to their online shopping cart but left without completing the purchase. It is one of the highest-converting email types in ecommerce.
Announcement Email
An announcement email is a dedicated campaign that communicates a specific update, milestone, or change to subscribers, from product launches and feature releases to company news and events.
ARPU (Average Revenue Per User)
ARPU (Average Revenue Per User) is a metric that measures the average revenue generated per email subscriber over a specific period, used to evaluate list value and campaign effectiveness.
Attention Rate
Attention rate is the percentage of email opens that last longer than 5 seconds, distinguishing genuine reads from passive opens, preview-pane views, or Apple MPP auto-loads.
B2B Email Marketing
B2B email marketing targets business professionals and organisations with longer sales cycles, educational content, and relationship-driven campaigns compared to B2C email.
B2C Email Marketing
B2C email marketing focuses on sending targeted promotional and transactional emails to individual consumers, emphasising personalisation, urgency, and direct response.