This research paper from Harvard Business School and Perplexity AI provides the first field evidence on how autonomous AI agents reshape knowledge work compared to conversational AI assistants. Using production data from Perplexity's Search and Computer products, the authors develop a task-based economic framework and examine four dimensions: adoption, autonomy, efficiency, and scope. The key finding is that Computer performs 26 minutes of autonomous work per session versus just 33 seconds for Search — a 48× increase — while reducing per-query dissatisfaction rates by 55%. On matched tasks, the agent reduces completion time from 269 to 36 minutes, yielding 87% time savings and 94% cost savings compared to humans using Search alone.

Beyond raw efficiency, the paper documents a fundamental expansion in the scope of work users attempt when given access to agents. Computer queries more frequently cross occupational boundaries, require higher-order cognition (71% abstract non-routine tasks vs. 53% for Search), draw on broader expertise domains (+38% more O*NET Knowledge domains per query), and bundle more subtasks into single queries. Notably, 23% of Computer queries involve task types that never appear in the same users' Search history, suggesting agents unlock entirely new categories of work rather than merely accelerating existing ones.

The conceptual framework elegantly captures the core tradeoff: agents have higher fixed delegation costs (specifying objectives, reviewing output) but lower marginal per-step execution costs, making them economically preferred for complex, multi-step tasks. User interviews corroborate the quantitative findings, with reported speedups ranging from 5× to 300× and cost reductions of two to three orders of magnitude. The paper also finds that Computer and Search are complements rather than substitutes — adopting Computer increases daily Search usage by approximately one additional query per day — consistent with the framework's prediction that agent-driven cost savings free up budget for shorter tasks where conversational tools retain an advantage.