Still, take a closer read of Vanguard’s paper last year: John Ameriks, global head of Vanguard Quantitative Equity Group and a member of the policy-setting Strategic Asset Allocation Committee, said he was “hesitant to call commodities an inflation hedge. Commodities show a very high correlation with unexpected inflation,” Ameriks said. “But over longer horizons, the relationship between the asset class and the broad rate of inflation is not so clear. You have to be careful in your analysis.”