A prioritized list of the riskiest assumptions about problem, solution, market, and business model exists.
Lean Startup
Prerequisite
What needs to be finished first
A Lean Canvas version or comparable business model sketch describes assumption fields (problem, solution, channels, revenue).
Preparation
What needs to be ready before start
Assumption backlog with priority; experiment template (hypothesis, method, sample, success criterion); tracking tool for learning reports (Notion, Confluence, Airtable); analytics setup for behavior; budget per cycle.
A founder or Product Lead as owner; one to three makers (cross-functional, often one PM, one designer, one engineer); an analyst for measurement setup; a sponsor with pivot/persevere mandate.
Vision and business model; prioritized assumption backlog; available data and target group; budget and time limit per cycle; known constraints (regulatory, technical).
Weeks to months per cycle, several cycles total
Define cycle cadence (for example 2-3 weeks per build-measure-learn). Create learning report template. Put pivot-persevere date in calendar. Secure sponsor mandate in writing.
Core question
The one question this method answers
Which riskiest assumption does the team test in the next cycle with minimal effort, and what measurable behavior confirms or contradicts it?
Flow
Marker: Phase
| Step | Duration | Action | Hint |
|---|---|---|---|
1Phase 1: Hypothesis and success criterion | 1-2 days | Formulate the riskiest open assumption as hypothesis: "We believe X does Y because Z. We will know we are right if we observe A in B people." Set success criterion before building the MVP. | Defining success after MVP build is confirmation bias. Define in advance what exactly constitutes confirmation and contradiction. |
2Phase 2: Build MVP | 3-10 days | Build the smallest possible version that allows measuring behavior. Options: landing page, concierge, wizard of oz, fake door, prototype. Build only essential engineering. | MVPs become products when building is enjoyable. Keep a strict cut: what is minimally needed to test behavior? Everything else waits. |
3Phase 3: Measure | 1-4 weeks depending on sample | Measure behavior quantitatively: conversion, clicks, payments, return visits. Reach minimum sample before interpreting. Capture raw data, not only aggregates. | Teams who interpret intermediate data often stop too early or bias results. Disciplined waiting for minimum sample is required. |
4Phase 4: Learn and report | 1-2 days | Check data against success criterion. Write learning report: hypothesis, setup, outcome, interpretation, open questions. Sponsor and team review. | A learning report without explicit outcome label (confirmed/disproved/open) has little effect. Outcome label is mandatory, even when negative. |
5Phase 5: Pivot or persevere | Half day | Decision: continue as planned (persevere), change strategy (pivot), or switch learning mode (measure differently). For each decision include rationale and next assumption. Sponsor signs. | A pivot without rationale is capitulation. Persevere without rationale is stubbornness. Every decision needs a learning-report reference, or the method becomes theater. |
Artifact
What comes out at the end
Learning report per cycle with hypothesis, MVP description, measurement setup, outcome, pivot/persevere decision, and next hypothesis. Plus ongoing assumption backlog with status (open, in test, confirmed, disproven).
One learning report per cycle with date and cycle number. Assumption backlog grows with status updates. Pivot decisions must refer to learning report; archive prior hypotheses.
- Notion or Confluence page per learning report
- Airtable experiment database
- Linear experiment issue type
- Google Docs for detailed learning reports
lean-startup-working-template.md
Compact working template for Lean Startup with context, input, output artifacts, and next step.
Lean Startup Working Template
Goal
Build-Measure-Learn cycles to validate business assumptions quickly and affordably.
Context
When and for what do we use this method?
Input
Which data, observations, decisions, or materials are available?
Execution
Short notes along the runsheet.
Output artifacts
- Hypothesis list:
- MVPs:
- Learning reports:
- Pivot or persevere decision:
Assumptions and open questions
- ...
Decision / next step
Owner, date, and success signal.
Example output
Concrete filled scenario, fictional example
lean-startup-beispiel.md
Concrete filled scenario, fictional example
Learning report cycle 4 — Solo Tax Advisory MVP (18.05.2026)
Hypothesis: We believe solo tax advisors in DACH will pay EUR 19/month for AI document capture because document capture is their largest time sink. Confirmation is when 25 of 50 contacted advisors proceed to confirmation page (50% conversion).
MVP: Landing page with pricing table (9/19/29 EUR), Stripe checkout in test mode (real cards not charged). Promoted via LinkedIn DM outreach (53 people contacted).
Measurement (2 weeks, 53 advisors contacted, 50 clicks):
- 19 EUR plan: 11 of 50 reached checkout (22%).
- 9 EUR plan: 27 of 50 (54%).
- 29 EUR plan: 4 of 50 (8%).
Outcome: Hypothesis disproved for 19 EUR. Confirmed for 9 EUR.
Interpretation: Willingness to pay is lower than assumed. Possible reasons: advisors compare with DATEV Company Online, which is already included in full DATEV plans. Value proposition needs clearer differentiation.
Decision (Sponsor @julia): Pivot pricing. Next hypothesis: switch target group to solo freelancers without accountants (likely higher willingness to pay). Test in cycle 5.
Assumption backlog update: A12 (pricing 19 EUR) disproved; A18 (solo freelancers pay 12-15 EUR) moved to top priority.
Pitfalls
Recognize symptoms and steer against them
MVP becomes product
MVP takes 3 months instead of 2 weeks because engineering builds "properly."
Define MVP as minimum to measure behavior. Evaluate wizard of oz, concierge, and fake door before full code. MVP build time should be max 25% of cycle time.
Success criterion set after test
Data arrives, team later interprets it as success, and confirmation becomes arbitrary.
Write success criterion before MVP build. Explicit minimum sample and minimum conversion. If incomplete, experiment is invalid.
Opinion instead of behavior
Surveys ask "would you use this," with positive answers but no one pays later.
Set measurement setup on behavior: click, payment, signup, retention. Surveys can complement, but not replace evidence.
No pivot despite disproving result
Learning report disproves the assumption but team continues building the disproven idea.
Schedule a fixed pivot-persevere review with sponsor. Disproval must have strategic consequence. Anyone continuing on disproven path needs another data point.
Hypothesis too weak
Hypothesis is trivial ("users want faster clarity") and confirmation is informationally empty.
A good hypothesis is risky: strategy would change if disproven. If pivot is not possible, the hypothesis was not risky enough.
No sample reflection
Only 8 clicks are measured; any interpretation has ±50% uncertainty.
Define minimum sample before test (for example 50 or 100). Mark results as open with smaller sample and extend cycle.
Stop criteria
Done signals checkable in under a minute
Finished the runsheet?
Go to the profile for purpose, similar methods, and sources or continue to the next method in the catalog.