06-reference

reforge growth models

Thu Apr 02 2026 20:00:00 GMT-0400 (Eastern Daylight Time) ·article ·source: https://program.reforge.com/c/growth-series-eg/growth-models ·by Reforge (Brian Balfour)

Reforge — Growth Models

Summary

A growth model answers one question: how does your product grow? The model must be built from the perspective of users (not capital), grounded in loops (not funnels), and kept simple enough to actually use. The core mental model is a three-tier modeling system — qualitative, loop-specific quantitative, and end-to-end quantitative — each serving a different purpose.

Why Most Growth Models Fail

Three common mistakes that render models useless:

  1. Wrong perspective — built around inflow/outflow of capital rather than users or customers.
  2. Wrong law — built on funnels rather than loops, which breaks the compounding logic.
  3. Pursuit of perfection — too detailed and complicated to use on a day-to-day or week-to-week basis.

Three Types of Growth Models

ModelBest ForLimitation
Qualitative modelCommunication, brainstorming, strategic alignmentLacks accuracy for prioritization and goal setting
Loop-specific quant modelValidating and prioritizing ideas within a single loopCannot show how multiple loops interact
End-to-end quant modelGoal setting, big strategic bets, directional predictionsToo complex for broad team communication

The right answer is to use all three for different purposes — not to pick one.

Building a Qualitative Growth Model

The qualitative model has three goals: (1) create an easy-to-communicate tool, (2) align team understanding and language, (3) identify and evaluate the strategic picture.

Four steps to build it:

  1. Define the output — what does the model produce? (Active users, revenue, etc.)
  2. Add habit/engagement loops — how do existing users keep coming back? Three trigger types: user-triggered, company-triggered, environment-triggered. See 06-reference/2026-04-03-reforge-engagement-activation for engagement loop mechanics.
  3. Add acquisition loops — how does one cohort lead to the next? Map the specific loop types from 06-reference/2026-04-03-reforge-acquisition-loops.
  4. Add linear channels — what non-looping activities feed the system?

Linear channels play two roles in the model: (a) feeding loops that are not self-sustaining, and (b) providing activation energy to get new loops spinning.

Growth Model and the Four Pillars

The growth model connects to the four strategic pillars from 06-reference/2026-04-03-reforge-defining-strategy:

A growth loop is a closed system: input (new or returning user) -> series of actions -> output that is directly reinvested as input. This definition applies to both acquisition loops and engagement loops.

Relevance to projects:

Connects to 06-reference/2026-04-03-reforge-defining-strategy (growth model as the bridge between mission and execution), 06-reference/2026-04-03-reforge-acquisition-loops (the acquisition layer of the model), 06-reference/2026-04-03-growth-loops-new-funnels (why loops replace funnels in the model), and 06-reference/2026-04-03-racecar-growth-framework (another visualization of the same growth system).

Open Questions