A new study from the University of Pennsylvania's Wharton School and consultancy GBK Collective finds that most companies still gauge AI's return by worker efficiency rather than revenue growth, making the payoff hard to demonstrate in financial statements. The study drew on online surveys of 1,400 U.S.-based employees at firms with at least 1,000 staff and more than $50 million in annual revenue. It found 40% of managers measured AI's impact as "hours saved per employee" and 37% tracked error reduction, while only about 27% tracked revenue from customer-facing AI features, apps and tools; 44% said AI's main role over the next one to two years will be productivity, and just 8% expected new revenue or new products.