> ## Documentation Index > Fetch the complete documentation index at: https://recurr.dev/docs/llms.txt > Use this file to discover all available pages before exploring further. # Multi-axis cohort selection > Five dimensions used to scope each migration wave: tenure, geo, engagement, renewal window, and plan. Tenure and engagement also drive the ongoing qualification trigger after the project. Cohorts aren't picked at random. Each wave targets a slice of the eligible base defined on five axes, each tested individually during the pilot so migration cohorts can sequence based on what cleared. ## The five axes How long the subscriber has been continuously paying. 12+ months on a renewal cycle behaves very differently from a 3-month new subscriber. Long-tenure cohorts often migrate at higher rates. Primary markets vs secondary. Compliance and reachability vary by region; payment-method support varies (e.g., SEPA, Brazilian Pix). Sequencing by geo lets you start where the path is clearest. Quintiles of in-app activity. High-engagement subscribers are typically easier migrations (they care about the app); low-engagement subscribers carry more churn risk on any touchpoint. Time until next renewal. Subscribers near a renewal cycle tend to be more receptive — the renewal is on their mind. Longer-window subscribers can wait, and waiting compounds the recovery. Annual vs monthly, premium vs basic, trial vs paid. Annual cohorts have different conversion mechanics than monthly (card-save vs early-charge); premium tier subscribers often have higher migration intent. ## How the axes get used The pilot samples across all five axes at once — a stratified slice of the base with every cohort represented, each measured separately so response can be attributed per cohort rather than averaged away. Two to three waves build a per-cohort read before the program scales. Migration waves then run stratified-parallel — every cohort starts in week one at a small allocation, and volume ramps wherever that cohort's benchmarks clear. Each wave's cohort spec tightens or widens based on what the prior waves showed. ## Ongoing qualification The five axes scope the project-phase migration. After that, the migration extends itself: new mobile cohorts continue to qualify as they cross the same thresholds the pilot validated. When a new cohort crosses the qualified band, the standardized migration sequence runs — branded email, web checkout that preserves the subscriber's existing economic terms, entitlement bridge — without per-cohort tuning. The thresholds were set during the pilot; new cohorts cross them as time and engagement accumulate. ## Why five and not more There are more axes you *could* split on (signup source, device tier, language, billing currency, etc.). Five is the count where: * The combinatorics stay tractable. Beyond five, the cohort space explodes and starves any individual cell of statistical power. * The axes are independently meaningful. Tenure, geo, engagement, renewal window, and plan all carry distinct migration-rate signal. Adding a sixth typically correlates with one already on the list. * The reporting fits on one screen. A wave summary that's one screen tall keeps the gating decision fast; a wave summary that scrolls is a slower decision. If your app has a meaningful axis we haven't named (e.g., a critical signup-source split), it gets folded in during the Migration Review. [Operational safeguards →](/framework/operational-safeguards)