Answer extracted from the Invest Like The Best podcast — listen to the full episode below.
How should venture investors balance conviction-based decision-making with seeking external validation on investment theses?
Start with instinctive conviction—rating opportunities an 8 or 9 immediately—then spend days or weeks grounding yourself in domain knowledge to expose blind spots. Rather than building conviction gradually, reverse the process: write detailed investment memos and solicit rigorous pushback from trusted advisors who challenge your logic, not your instinct alone.
Sarah's approach flips the traditional venture playbook. Most investors accumulate evidence until conviction builds gradually. She begins at conviction, then systematically works backward to test whether the conviction holds. This isn't recklessness—it's a deliberate method for separating signal from noise in a rapidly evolving domain.
The initial instinct is critical: Sarah rates people and ideas almost immediately, often at 8 or 9 on her conviction scale. But this is only the opening move. The real work begins in the following days and weeks, when she immerses herself in the specific domain to understand what gaps exist in her own judgment.
As Sarah explains in her episode on Invest Like The Best, she doesn't make decisions in isolation. Instead, she writes full investment memos in Greylock style—rigorous documents that articulate her thesis—and shares them with trusted investor advisors like John Lilly or Dylan Field. These aren't Yes/No votes; they are direct challenges to her reasoning.
The quality of external validation matters enormously. Sarah deliberately seeks pushback on logic and thesis, not validation of her instinct. She wants people to challenge the underlying arguments, to poke holes in her reasoning, to expose what she might be missing about the market, the team, or the technology itself. This is markedly different from asking advisors whether they like the idea.
Sarah — Investor, Greylock. Sarah is an early-stage investor focused on AI, biology, defense, and robotics who co-founded or leads a venture fund with partners including Mike, Pranav, and Bella. She chose investing after realizing she is deeply curious, values understanding things deeply, and is motivated by working with extraordinary people and using her skills to make them more successful. Her conviction-based approach has shaped how she evaluates emerging technologies and high-agency founders across the frontier of innovation.
The psychological advantage of starting at conviction is clarity. If you begin uncertain and build conviction, you are vulnerable to confirmation bias—seeking evidence that supports your emerging belief. If you start at conviction and actively work to dismantle it, you force yourself to find genuine weaknesses. You're not looking for supporting data; you're hunting for what's wrong.
What makes this process distinct from pure conviction bias is the structured commitment to domain expertise and rigorous memo writing. Sarah doesn't stop at gut feel. She researches deeply, writes formally, and invites public dissection. The conviction is the starting fuel; the validation loop is the refinement engine.
One detail worth listening to in depth: how Sarah navigates the specific AI investment landscape where everyone is moving at 90 miles an hour, trying to press the brakes while simultaneously accelerating. Her conviction-based framework within a hyper-competitive field offers a concrete model for other investors facing similar paralysis. Discover more in the full episode.
See also
What decision-making framework should investors use when evaluating AI companies in a period of rapid technological change?
Sarah emphasizes taking a very specific view of what is now possible, then determining what is valuable within what is possible, and identifying who is capable of executing that vision.
Key takeaways
- Start with instinctive conviction (rating 8–9), then systematically deconstruct it over days or weeks through domain research.
- Write formal investment memos and share them with trusted advisors who will challenge your logic, not simply validate your instinct.
- Seek pushback on your thesis and reasoning, not external validation of whether the idea is good.
- Work backward from conviction to test whether it holds, reversing the traditional gradual-confidence-building approach.