The Program for the International Assessment of Adult Competencies (PIAAC), administered by the Organization for Economic Cooperation and Development (OECD), evaluates cognitive and workplace skills of adults aged 1674 globally. It assesses literacy, numeracy, and problem-solving in technology-rich environments, focusing on skills critical for 21st-century societal and economic participation. The U.S. National Center for Education Statistics (NCES) leads its implementation domestically. PIAACs primary purpose is to compare adult competencies across countries, analyze relationships between skills and outcomes (e.g., employment, income, education), and inform policy on education and workforce training. It provides data to evaluate education systems and design interventions to enhance skill development. Key features include its cyclical, large-scale design (with data collection rounds every 57 years), cross-country comparability, and inclusion of contextual background information on participants education, work, and demographics. Unique aspects are its focus on both foundational skills (e.g., reading, math) and complex problem-solving, as well as its role in tracking skill trends over time. The dataset supports research on social mobility, economic productivity, and the impact of globalization on workforce readiness. (Word count: 198)