WHAT MAKES A GOOD PRODUCT-MARKET FIT METRIC?

Summary from the TLDR Founders newsletter

A good product-market fit (PMF) metric should accurately signal when a product is ready for broader distribution, minimizing false positives that lead to premature scaling and false negatives that delay growth. Cohort retention rate is a stronger PMF indicator than survey-based metrics like NPS and the "40% very disappointed" rule, which have limitations, as it captures actual user behavior over time without response bias. Benchmarks for PMF cohort retention vary by product type, with 25%+ for consumer and 70%+ for B2B SaaS, and the best products often exceed 40% and 80% respectively.