An interesting comment from Mauldin Economics on the US Federal Reserve that reinforces a scientific principle built into the Improvement Kata. Running experiments with only one variable is such an important principle yet requires great discipline.

‘No serious scientist would run a two-variable experiment. By that I mean, you run an experiment with one variable to see what happens. If you have two variables in your experiment and something either good or bad happens, you don’t know which variable was the cause. You first run the experiment with one variable, then do it again with the second one. After that, you have the knowledge to run an experiment with both of them.

The Federal Reserve is running a two-variable experiment without the benefit of ever having run a one-variable experiment to determine what the results would be. It is decidedly the stupidest monetary policy mistake in a long line of Fed mistakes.

What are the two variables? They are raising interest rates (albeit slowly) and aggressively reducing their balance sheet. I think many of the problems we see in the market are results of this combination. They should do one or the other, not both.’