[fdr]

You don't even need to trust CPI alone when looking in history, where things have evened out a bit: we have historical short-term bond yield data, even the yield curve: people bidding on short periods with the safest debtor expecting changes in nominal value.

Not to suggest CPI is redundant, there's a reason why central bankers read it after all. For one, it's the most timely data they have. But it's impossible to nudge it year after year -- accumulative error -- without it become obviously decoupled from other data, including the long-term bond market data. It just so happens commodities are the wrong yardstick.