Direct Alpha (Gredil-Griffiths-Stucke; also called Long-Nickels methodology) — a money-weighted IRR-based PME variant comparing PE fund returns to public-market returns on a cash-flow-matched basis. Methodology: (1) construct a shadow portfolio of a chosen public-market index; (2) apply each PE fund cash flow to the shadow portfolio (contributions buy index shares, distributions sell index shares); (3) compute the IRR of the shadow portfolio; (4) Direct Alpha = Fund IRR − Shadow IRR. A +2.5% direct alpha means the PE fund outperformed the public-market shadow portfolio by 2.5 percentage points of IRR on a cash-flow-matched basis. Used by sophisticated LPs to assess whether PE is delivering its theoretical illiquidity premium.