Definition
Stop reporting motion as if it were progress
Activity is what the company did. Evidence is what changed outside the company because of it.
Startup reporting is dominated by activity because activity is always available, always improving and entirely under the company's control. Evidence is scarce and often unflattering, which is exactly why it is the only reliable basis for an irreversible decision.
Direct answer
What is evidence versus activity?
Evidence is a change in external behaviour caused by the company's work; activity is the work itself, and no amount of it substitutes for evidence.
Deeper explanation
What it proves
- That something outside the company changed
- That the change can be attributed to specific work
What it does not prove
- That the change will repeat
- That the change is large enough for the next decision
- That the team is working effectively
Common false signals
- Meetings held, demos given, features shipped, decks produced
- Vanity metrics with no downstream behaviour
- Roadmap completion presented as market progress
- Fundraising milestones reported as customer validation
- Content, awards and press treated as demand
Founder implications
- Your weekly review separates what you did from what changed outside.
- You allow a week of high activity to be reported as low evidence.
Investor implications
- You read updates for external behaviour and treat the rest as context.
- You ask what changed outside the company since the last update.
Board implications
- You ask for evidence first and activity second, in every pack.
- You reward accurate reporting of weak evidence rather than punishing it.
A two-column reporting habit
One column: what we did. Another column: what changed outside as a result. When the second column is empty for several weeks, that is information, not a presentation problem.
Where this sits in the book and the OS ebooks
More Scars Than Trophies explains evidence versus activity as theory: why the distinction exists and how it changes judgement. The Proof Stack OS ebooks turn it into operating practice, and each OS ebook has its own separate role-specific AI chatbot.
- Proof Stack Daily OS: The founder's operating system for turning proof into daily decisions.
- Proof Stack Company OS: The company and board operating system for evidence-based governance.
- Proof Stack Investor OS: The angel investor's operating system for evidence-based startup decisions.
Evidence boundaries
What this page does not claim
The limits of the model are stated on the page, not buried in a footnote.
- Activity is necessary; the model does not treat it as waste. It treats it as an unreliable proxy.
- Attribution is imperfect, and the model does not claim to resolve it.
Audience implications
What changes for each reader
The same evidence standard, read from three different seats.
Founders
- Your weekly review separates what you did from what changed outside.
- You allow a week of high activity to be reported as low evidence.
Investors
- You read updates for external behaviour and treat the rest as context.
- You ask what changed outside the company since the last update.
Boards
- You ask for evidence first and activity second, in every pack.
- You reward accurate reporting of weak evidence rather than punishing it.
Author
Petri Lehmuskoski
Petri Lehmuskoski has founded, scaled, repaired and exited companies over more than four decades. He is Founding & General Partner of Gorilla Capital.
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Related
Continue through the model
- Stage-matched proof
Stage-matched proof is external behaviour strong enough to justify the next irreversible decision at the company's current stage.
- Governance without theatre
Governance without theatre is board practice in which decisions are tested against a stated evidence standard before they become irreversible, rather than reviewed after the fact through presentations.
- The Proof Stack
The Proof Stack is an ordered model of the evidence a company must hold before a decision that is difficult to reverse: a Discovery stage followed by four Proof layers (Buyer Proof, Value Proof, Scaling Proof and Exit Proof).
A plain-text version of this evidence layer, generated from the same page content, is available at /concepts.md.
Read the chapter that starts the argument
Chapter 1: Most Founders Do Not Fail Because They Make Bad Decisions. Free to read now, no email required.