Do AI Activity Indices Really Measure AI Activity?

AI dashboards report activity as a ratio, and a ratio hides which of its two counts moved. This paper proves that a regression on such a published index cannot identify a causal effect at any magnitude, that disclosing the denominator removes one bias channel but not the other, and that a design whose variation sits in two or three clusters has a detection floor above its own estimate — then shows all three binding on OECD.AI’s hiring index and Eurostat employment.