The practice of a PM personally engaging with both qualitative user/customer data (direct conversations, observation) and quantitative usage/purchase data (e.g., via a CRM like Salesforce.com and a data warehouse), rather than delegating interpretation to analysts or researchers.
The point isn't to replace Product Sense with data, nor to outsource it — it's that a PM's judgment sharpens only when they've sat with both kinds of evidence firsthand. This is one of the Four Sources of Insight (for Product Strategy) in practice, and it overlaps with Continuous Listening Across Teams: the PM doesn't wait for a synthesized report, they go look themselves.
See also Data-Driven vs. Data-Informed: A Skeptical Take for the caution against over-indexing on the quantitative half of this practice.
Even strong quantitative/qualitative research staff don't substitute for the PM personally engaging with the data. Cagan calls the older model — research delivered as a polished report months later — 'useless,' because teams discount findings they weren't personally involved in gathering. Immersion has to be first-hand; a summary handed down doesn't transfer the conviction or nuance.
Apply: when a team has dedicated researchers, still get the PM (and ideally the trio) into the raw sessions/data directly — don't let a research function become a proxy that removes the PM from the data.
Biddle treats qualitative empathy work — asking how a product makes people feel, studying competitors' products directly, and having one-on-one conversations with customers — as equally important to quantitative A/B testing, not a softer supplement to it. He uses it alongside frameworks like DHM Framework (Delight, Hard-to-Copy, Margin-Enhancing) to build the qualitative case for a product decision.