Final answer:
The first ever national assessment designed to measure adults' ability to read and understand health-related information is the Programme for International Assessment of Adult Competencies (PIAAC). It is a survey conducted by the OECD that tests adults on their skills in literacy, numeracy, and problem solving. This assessment provides important information on the health literacy levels of adults.
Step-by-step explanation:
The first ever national assessment designed specifically to measure adults' ability to use literacy skills to read and understand health-related information is called the Programme for International Assessment of Adult Competencies (PIAAC). It is a survey conducted by the OECD that tests adults aged sixteen to sixty-five on their skills in literacy, numeracy, and problem solving in technology-rich environments. This assessment provides valuable insights into the health literacy levels of adults in different countries.