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Define Hypothesis

  • 538 installs
  • 518 repo stars
  • Updated August 4, 2026
  • product-on-purpose/pm-skills

define-hypothesis is a product-management agent skill that turns assumptions into testable hypothesis statements with metrics and validation plans for developers and PMs scoping experiments before building features.

About

define-hypothesis is a pm-skills agent skill from product-on-purpose/pm-skills that structures testable product hypotheses before engineering investment. Invoked as /pm-skills:define-hypothesis, it walks through belief articulation, target user segments, expected outcomes, primary and guardrail metrics, validation approach, and documented risks. Developers and PMs reach for define-hypothesis after a problem statement and before PRDs, solution briefs, or experiment-design skills in the pm-skills recipe chains. Output follows the template: We believe that [action] for [user] will [outcome] as measured by [metric], plus validation and assumption sections. The skill prevents shipping features on untested beliefs by making success criteria explicit and shared.

  • define-hypothesis
  • AI & Agent Building
  • AI-coding skill

Define Hypothesis by the numbers

  • 538 all-time installs (skills.sh)
  • +30 installs in the week ending Aug 4, 2026 (Skillselion tracking)
  • Ranked #1,695 of 16,546 AI & Agent Building skills by installs in the Skillselion catalog
  • Data as of Aug 5, 2026 (Skillselion catalog sync)
npx skills add https://github.com/product-on-purpose/pm-skills --skill define-hypothesis

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Listed on Skillselion
Installs538
repo stars518
Last updatedAugust 4, 2026
Repositoryproduct-on-purpose/pm-skills

How do you write a testable product hypothesis with metrics?

Helps with ai & agent building tasks.

Who is it for?

Engineers and PMs moving from problem statements to experiments who need explicit, measurable beliefs before solution or PRD work.

Skip if: Teams already past validation with approved PRDs, pure technical implementation tasks, or problems lacking a defined user segment.

When should I use this skill?

User asks to define a hypothesis, test an assumption, set experiment metrics, or chain from a problem statement before building.

What you get

Structured hypothesis statement, target user segment, primary and guardrail metrics, validation plan, and documented risks and assumptions.

  • Hypothesis statement document
  • Success and guardrail metrics
  • Validation approach and risk notes

Files

SKILL.mdMarkdownGitHub ↗

<!-- PM-Skills | https://github.com/product-on-purpose/pm-skills | Apache 2.0 -->

Hypothesis

A hypothesis is a testable prediction about how a change will affect user behavior or business outcomes. It transforms assumptions into explicit statements that can be validated or invalidated through experimentation. Well-formed hypotheses prevent teams from building features based on untested beliefs and create shared understanding of what success looks like.

When to Use

  • After problem framing, before committing to a solution
  • When designing experiments or A/B tests
  • When team members have differing assumptions about user behavior
  • Before investing significant engineering resources in a feature
  • When pivoting direction and need to validate the new approach

When NOT to Use

  • You are ready to design the actual A/B test (variants, sample size, duration) -> use measure-experiment-design; this skill frames what to test, not how
  • The problem itself is still unframed -> use define-problem-statement first
  • You want to organize many assumptions and ideas into a discovery structure -> use define-opportunity-tree
  • The team needs the full business-model picture, not one testable claim -> use foundation-lean-canvas

Instructions

When asked to create a hypothesis, follow these steps:

1. State the Belief Articulate what you believe will happen. Use the structured format: "We believe that [action/change] for [target user] will [expected outcome]." Be specific about the intervention - vague hypotheses can't be tested.

2. Identify the Target User Define who this hypothesis applies to. A hypothesis about "users" is too broad. Specify the segment: new users in their first week, power users with 10+ sessions, churned users returning, etc.

3. Define the Expected Outcome What behavior change or result do you expect? Frame it in terms of user actions (complete onboarding, make a purchase, return within 7 days) rather than internal metrics when possible.

4. Set Success Metrics Choose a primary metric that directly measures the expected outcome. Include secondary metrics that provide context and guardrail metrics that ensure you're not causing harm elsewhere.

5. Describe Validation Approach How will you test this hypothesis? A/B test, user interviews, prototype testing, cohort analysis? Be specific about sample size, duration, and statistical requirements.

6. Document Risks and Assumptions What could invalidate this hypothesis beyond the test results? What are you assuming to be true that you haven't validated?

Output Format

Use the template in references/TEMPLATE.md to structure the output. A complete hypothesis document fills every template section: Hypothesis Statement; Background & Rationale; Target User Segment; Success Metrics; Validation Approach; Risks & Assumptions; and Timeline.

Quality Checklist

Before finalizing, verify:

  • [ ] Hypothesis is falsifiable (possible to prove wrong)
  • [ ] Success metric has a specific numeric target
  • [ ] Target user segment is clearly defined
  • [ ] Validation approach is practical and time-bound
  • [ ] Pass/fail criteria are unambiguous
  • [ ] Hypothesis doesn't assume the solution works

Examples

See references/EXAMPLE.md for a completed example.

Related skills

How it compares

Use define-hypothesis before PRD or experiment-design skills when the gap is an untested belief, not requirements detail or instrumentation specs.

FAQ

How do you invoke define-hypothesis in Claude Code?

define-hypothesis is invoked with /pm-skills:define-hypothesis plus context, or $define-hypothesis on Codex. The skill outputs a structured belief statement, metrics, validation plan, and risks.

What should come before define-hypothesis in pm-skills?

define-hypothesis typically follows define-problem-statement in pm-skills recipe chains. Problem framing supplies user pain and context; the hypothesis skill adds testable beliefs and measurable outcomes.

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