I feel like we have made inflation deceptively simple. We have this exact number for it. The Bureau of Statistics will declare something like “last month, the inflation was 2.46%, annually adjusted.” It will do so with an number that is so precise that at will have at least two decimals, implying the surgical accuracy employed to get to that particular number.
We don’t seem to ask ourselves how we come up with these number, do we?
Do We Even Know What Inflation Is?
The great Milton Friedman did not have even a shadow of a doubt: “Inflation is always and everywhere a monetary phenomenon.” Well, here is what the equally great Robert Solow said about Milton Friedman: “Another difference between Milton [Friedman] and myself is that everything reminds Milton of the money supply. Well, everything reminds me of sex, but I keep it out of my papers.”
In Japan they have been expanding the money supply for decades. They can’t seem to produce inflation, no matter how hard they try. If we ask the European Central Bank what inflation is, they say something like “inflation occurs when there is a general rise in prices.” (They will also ask if you have seen the inflation monster and offer you to watch a cartoon about price stability).
If inflation is just general rise in prices, then why do prices rise or fall? Most would say, because changes in supply and demand. Don’t prices of products and services tend to drop over time? How do we even measure this?
How to Measure Inflation?
This seams to me an exceptionally tricky undertaking. If inflation is supposed to measure changes in the price of the stuff we buy over a period of time, what happens when we start buying different stuff over time? Our behaviors and preferences are constantly changing? Imagine a lab scientist that has to test his experiment on rats one day and then repeat the experiments with hamsters.
Do you see the problem here? The stuff we buy is not constant. Take mobile phones for example. How can you realistically measure the inflation in mobile phones from one year to another? Or even, how do you compare the price inflation of mobile phones to a period 20 years ago, when there were no mobile phones?
What about all the stuff we don’t pay for yet derive some benefit from? How do you factor in the change in cost of consuming Google searches into any inflation measurement? Should you measure the increase and decrease in paid ads displayed with organic searches?
And there there are substitute products. If pork rises in value, relative to beef, you might be inclined to consume more beef and less pork. But the baskets of goods and services will take that into account.
So next time, when you see an inflation number with a couple of decimal points. Ask yourself how it was measured and how accurate that measurement could be.
How to Value Stuff 