The document discusses various methods of data collection for adult learner enrollment management, including both primary and secondary data techniques. It outlines the merits and demerits of each method, such as direct personal investigation, indirect oral investigation, and the use of questionnaires and schedules, emphasizing considerations of accuracy, cost, and suitability. Additionally, it notes the importance of published and unpublished sources for gathering secondary data and highlights potential issues with accuracy and adherence to research standards.