Quality Of Evidence

What We Cover in This Episode

• Why product teams are drowning in data — but still making uninformed decisions

• The danger of projecting your own expertise onto low-quality signals

• Teresa's "ladder of evidence" framework: as effort goes up, so does value

• Henrik Kniberg's triangle (Petra's coaching go-to): quantitative data + organizational signal + qualitative insight

• What Teresa is learning from real interview transcripts at Vistaly — and why many "interviews" aren't really interviews

• The spectrum of interview quality: story-based interviews vs. direct-question interviews vs. usability preference gathering

• Why product demos and stakeholder meetings are being mistaken for customer research

• How to communicate signal strength without discouraging teams from interviewing

• The strategic product decision behind Vistaly's choice to support imperfect interview formats — and use them as coaching moments

• Why vibe-coded software makes good interviewing skills more critical than ever

Key Concepts & Frameworks

• Ladder of Evidence — Teresa's framework for thinking about evidence quality. Low-effort signals (support tickets, app store reviews, sales call notes) are abundant but carry weak signal strength. High-effort, story-based interviews are harder to collect but carry far more context for decision-making.

• Story-Based Interviewing — Rather than asking customers about preferences or opinions, story-based interviews collect the narrative of a specific experience: what were you trying to do, when did this come up, what went wrong, what did you need? This context is what makes evidence actionable.

• Signal vs. Insight — Low-quality signals tell you something is worth exploring. They rarely tell you what to build. The risk: product experts fill in the gaps with their own assumptions and get it wrong.

Quotes Worth Saving

"We're inundated with these low-value signals all the time, but they rarely carry enough signal strength to actually tell us what we should be building. But they feel like they do." — Teresa Torres

"The worst thing you could do is never talk to a customer. The best thing you can do is collect a really rich story about their experience." — Teresa Torres

"It is easier than ever to release mediocre software. People need to get better at interviewing." — Petra Wille

Resources & Links:

• Follow Teresa Torres: ProductTalk.org

• Follow Petra Wille: Petra-Wille.com

Mentioned in this episode:

• Teresa’s blog:

Ask Teresa: What Should You Do With Insights That Don’t Come from Customer Interviews? (producttalk.org/other-insights)

Story-Based Customer Interviews Unlock Missing Context (producttalk.org/story-based-customer-interviews)

The Ladder of Evidence: Get More Value From Your Customer Interviews and Product Experiments (producttalk.org/ladder-of-evidence)

• Learn more about story-based customer interviews in Teresa’s course: Story-Based Customer Interviews (learn.producttalk.org/course/story-based-custo…)

• Henrik Kniberg (linkedin.com/in/hkniberg)'s Triangle — a framework Petra uses in coaching (images.squarespace-cdn.com/content/v1/5dc1d3bd…) to ensure teams triangulate quantitative data, organizational signal, and qualitative evidence before acting

Minimise the Gap Between Maker and User by Henrik Kniberg (mindtheproduct.com/minimise-the-gap-between-ma…)

• Vistaly (vistaly.com) — Teresa's partnership for AI-generated interview snapshots and opportunity solution trees