Beyond Exposure: Predicting AI Adoption Based on Comparative Advantage

We document and explain the gap between measures of AI exposure and measures of AI adoption in the workplace.This leads us to propose a new AI adoption index based on comparative advantage.Using the representative German DiWaBe employee survey linked to worker and establishment information, we compare worker-reported AI use to prominent exposure measures and find that the relationship is weak.Motivated by this gap, we develop a framework in which adoption depends not only on technical feasibility (i.e., AI's absolute advantage measured by exposure) but on profitability (i.e., AI's comparative (dis)advantage relative to a specific worker), balancing AI productivity against AI user costs and worker productivity against wages.We operationalize this framework at the task level by (i) estimating worker productivity relative to pay, (ii) mapping exposure indices into AI productivity, and (iii) inferring task-specific AI user costs from revealed-preference adoption.The resulting occupation-level index accounts for almost 60% of cross-occupation variation in observed AI adoption, compared to 14% for an exposure-only model.The two approaches diverge substantially for approximately 30% of workers, highlighting that comparative advantage-not exposure alone-is crucial for assessing AI's labor-market impact.