What is list growth rate, and how do you measure it in Metabase?

List growth rate is the net change in your email list per period — new subscribers minus unsubscribes, hard bounces, and pruned addresses, divided by list size. It's the compounding engine behind every other email metric: a list that shrinks quietly caps everything downstream. Measure it in Metabase from subscriber data synced from Klaviyo, Mailchimp, ActiveCampaign, or SendGrid.

What list growth rate measures

It measures whether your audience is compounding or decaying. Gross growth — raw signups — is a form-performance metric; net growth subtracts everyone who left through the exits (opt-outs, dead addresses, pruning) and tells you what actually happened to the list. Most lists lose 20-30% of subscribers a year to natural decay, so acquisition has to outrun churn just to stay flat.

Two refinements make it a real instrument. First, source attribution: tag every subscriber with the form, page, or channel that acquired them, so growth decomposes into things you can act on. Second, a quality guardrail: compare each new cohort's early engagement against tenured subscribers. Volume from a source whose subscribers never open dilutes engagement rate and drags on deliverability — the list got bigger and worse at the same time.

What data does it need?

• A subscribers table with subscribed_at, status, and acquisition_source (form, landing page, channel, import) — synced to your warehouse via Airbyte, Fivetran, or dlt.
• Exit events with reasons: unsubscribed, hard bounced, pruned/suppressed — each dated, so components can be trended separately.
• A daily or monthly list-size snapshot (or a running balance modeled from the change events) for the denominator.
• Per-subscriber engagement rollups (opens and clicks in the first 90 days) to score new-cohort quality by source.

SQL patterns

SELECT
  date_trunc('month', d.event_date) AS month,
  SUM(d.new_subscribers) AS new_subscribers,
  SUM(d.unsubscribes)    AS unsubscribes,
  SUM(d.hard_bounces)    AS hard_bounces,
  SUM(d.pruned)          AS pruned,
  SUM(
    d.new_subscribers - d.unsubscribes - d.hard_bounces - d.pruned
  ) AS net_change,
  ROUND(
    100.0 * SUM(
      d.new_subscribers - d.unsubscribes - d.hard_bounces - d.pruned
    ) / NULLIF(
      -- the month's starting balance is the earliest daily snapshot,
      -- not the smallest value the list dipped to during the month
      (array_agg(d.list_size_start ORDER BY d.event_date))[1], 0
    ), 2
  ) AS net_growth_rate_pct
FROM list_changes_daily d
WHERE d.event_date >= CURRENT_DATE - INTERVAL '12 months'
GROUP BY 1
ORDER BY 1;

SELECT
  s.acquisition_source,
  COUNT(*) AS new_subscribers,
  ROUND(
    100.0 * COUNT(*) FILTER (
      WHERE e.opens_90d > 0 OR e.clicks_90d > 0
    ) / NULLIF(COUNT(*), 0), 1
  ) AS engaged_90d_pct,
  ROUND(
    100.0 * COUNT(*) FILTER (WHERE e.unsubscribed_90d)
    / NULLIF(COUNT(*), 0), 2
  ) AS churned_90d_pct
FROM subscribers s
JOIN subscriber_engagement_90d e ON e.subscriber_id = s.id
WHERE s.subscribed_at >= CURRENT_DATE - INTERVAL '6 months'
  AND s.subscribed_at < CURRENT_DATE - INTERVAL '90 days'
GROUP BY 1
ORDER BY engaged_90d_pct DESC;

Pitfalls

Where this metric applies

• Klaviyo + Metabase — profile lifecycle and suppression events by source
• Mailchimp + Metabase — audience growth, unsubscribes, and cleaned addresses
• ActiveCampaign + Metabase — contact status changes and list membership
• HubSpot + Metabase — contact lifecycle and email subscription status

Related

Metrics

Dashboards

FAQ