measuring▌

Framework-based assessment of product-market fit using signals from 46 product leaders. \n \n Apply the Sean Ellis \"very disappointed\" survey as a leading PMF indicator, targeting 40% threshold before long-term retention data is available \n Diagnose stage through retention curves, reference customer counts, and customer pull signals; distinguish between vanity metrics and genuine PMF evidence \n Recognize PMF across four levels (nascent to extreme) with segment-specific fit; understand that P