bPMF (Behavioral Product‑Market Fit)
Definition: bPMF is the share of users in a defined cohort who complete the validated target behavior at or above the frequency threshold within the evaluation window.
Canonical threshold: bPMF ≥ 0.70 for 2+ consecutive cohorts (default windows and cohorts below). This is a practitioner heuristic; calibrate by domain and stakes.
Why it matters: It anchors Product‑Market Fit to the behaviors that actually create value, not to proxies like installs or revenue spikes decoupled from the target behavior.
Cohort construction (read first)
Default: 30‑day acquisition cohorts
- Cohorting: Users first seen (acquired) during the calendar month (or any 30‑day rolling window).
- Window: Measure target‑behavior completion within 30 days of first seen.
- Denominator: All acquired users in the cohort (state exposure rules explicitly if access is gated).
- Behavior threshold: Use the pre‑registered frequency/quality threshold from the Decision Memo (e.g., “≥ 3 uploads in 30d” or “≥ 1 certified dataset published with complete metadata”).
When to deviate (state exceptions explicitly)
- Long‑cycle B2B (procurement/governance): use 60/90/120‑day windows and justify choice.
- Event‑based value (e.g., tax filing): use event‑anchored windows (e.g., “within 14 days of request”).
- Mature‑use products (learning period): measure post‑activation cohorts, but disclose the activation definition.
- Seasonality: roll up by season and report bPMF per season with deltas to baseline seasons.
Reporting standard
- Cohort definition, window, denominator, behavior threshold.
- bPMF for the last ≥ 3 cohorts, plus D30/D180 behavior retention distributions.
- Segment by the limiting BSM component where possible.
Anti‑pattern: Declaring PMF on revenue or DAU without behavior retention evidence (bPMF).
Worked Example
Scenario: A fitness app validates “complete 3+ workouts per week” as the target behavior.
January cohort (acquired users): 500
Users completing ≥3 workouts/week within 30 days: 380
bPMF = 380 / 500 = 0.76 (76%)
February cohort: 520 acquired, 395 hit threshold → bPMF = 0.76
Assessment: bPMF ≥ 0.70 sustained for 2 consecutive cohorts. This product has achieved behavioral Product-Market Fit for the validated target behavior.
Case Studies
- Slack vs Glitch: Same Team, Different Behavior Fit: Why early team activation and behavior retention is the real signal