The Anthropic Economic Index is an initiative aimed at understanding AI's effects on labor markets and the economy over time. The index provides first-of-its-kind data and analysis based on millions of anonymized conversations on Claude.ai, revealing how AI is being incorporated into real-world tasks across the modern economy. The initial report shows that AI use is concentrated in software development and technical writing tasks, with around 36% of occupations using AI for at least a quarter of their associated tasks. AI leans more towards augmentation (57%) than automation (43%), with mid-to-high wage occupations like computer programmers and data scientists being the heaviest users of AI. The index also provides insights into how AI is changing the labor market, including the fact that very few occupations see AI use across most of their associated tasks, but more moderate use of AI is widespread. The dataset used for this analysis will be openly sourced to allow researchers to build on and extend the findings.