A family of benchmarks comparing PE fund cash flows to investing the same cash flows in a public-market index. Two main variants: (i) Kaplan-Schoar PME (KS-PME, multiple-based): KS-PME = sum_t D_t/I_t div sum_t C_t/I_t — values >1.0x indicate outperformance vs. the index; (ii) Long-Nickels / Direct Alpha (rate-based): construct a shadow portfolio in the index that receives each contribution and distribution as they occur, compute the shadow IRR, and report the spread (Direct Alpha = Fund IRR − Shadow IRR). PME is the cleanest test of whether PE is delivering its illiquidity premium.