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Success case

Clue: 3X users retained at 6 months across more than 120 countries

Clue is a female health and menstrual cycle tracking app present in more than 190 countries. For its global expansion, the measure of success was not install volume but genuine retention: users who remained active on the platform six months after acquisition. Zenda built the measurement and classification strategy that made it possible to operate that standard at global scale.

3XNew users retained after 6 months.
4 millionadditional monthly active users (MAU)
+120 countriesreached by acquisition campaigns

The challenge

Clue runs acquisition campaigns across more than 120 countries with widely different audiences, costs, and retention behaviors. The problem was not generating installs: it was knowing which channels and campaigns produced users who were still active six months later, and at what real cost.

  • Conventional acquisition metrics (CPI, install CPA) did not reflect the long-term value of each acquired user.
  • Geographic dispersion made it impossible to compare performance across countries without a classification system that weighted market quality.
  • Without an operational definition of retention as the central KPI, budget was allocated with no visibility into which channels and segments were driving sustainable growth.

Our approach

We designed a measurement strategy centered on 6-month retention as the reference metric, connecting every dollar spent per channel and campaign to actual user behavior over that time horizon.

  1. 01

    Cost per retention as the unit of purchase

    We redefined the primary acquisition KPI: instead of cost per install, we measured cost per user retained at 6 months, by channel and by campaign. This allowed channels with very different cost structures to be compared on a common basis.

  2. 02

    Tier classification weighted by country quality

    We developed a Tier system that weighted each market by its retention history and local acquisition cost. Countries with the best retention-to-cost ratio received budget priority; underperforming ones were reviewed or phased out.

  3. 03

    Consistent global measurement across +120 countries

    We implemented the measurement model uniformly across the full campaign portfolio, producing a unified view of performance by channel, campaign, and country under the same retention definition.

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