This paper revisits the golden constant – gold’s property of keeping constant purchasing power – via a comparison with a set of 17 commodities (energy, metals and agricultural products). We use graphical devices of the CPI-deflated commodity prices first, then stationarity tests designed to assess how fast the real prices of the commodities revert to their “constant” and, finally, measurements of their convergence speed. We find that the real price of gold is far from constant, farther than the real price of most other commodities. We also note that the mean reversion of gold’s real price to its constant/average is weaker and slower than that for most other commodities. These findings suggest that most commodities perform better than gold when it comes to keeping constant purchasing power. A portfolio of commodities would provide liquidity similar to that of gold while offering investors more stable protection against inflation.

本文通过与一组 17 种商品（能源、金属和农产品）的比较，重新审视了黄金常数——黄金保持恒定购买力的特性。我们首先使用 CPI 缩减商品价格的图形设备，然后使用旨在评估商品的实际价格多快恢复到“常数”的平稳性测试，最后，测量它们的收敛速度。我们发现黄金的实际价格远非恒定，远高于大多数其他商品的实际价格。我们还注意到，与大多数其他商品相比，黄金实际价格向其恒定/平均值的均值回归更弱且更慢。这些发现表明，在保持恒定购买力方面，大多数商品的表现都优于黄金。