A method is the way to a goal. For a simple goal, one method might be enough. If the goal is complex many methods have to be applied in a logical order and several subgoals must be achieved before it is possible to reach the final goal. A comprehensive plan is necessary. In research this plan is called “research design”.
“The conceptual phase is the initial phase of research and involves the intellectual process of developing a research idea into a realistic and appropriate research design. … The research design is the overall plan for conducting a study that will optimize the ability to achieve the study purpose and obtain accurate results.” (, Design Decision in Research: The Conceptual Phase - Page 4, The Design and Planning Phase - Page 11, 10.08.19)
“The term ‘design’ describes the overall plan and structure of a peace of research … A design can be regarded as the framework into which particular methods are fitted. … Research methods are the specific techniques employed in the execution of a piece of research.” (Sim J, Wright C (2000) Research in Health Care: Concepts, Designs and Methods. Cheltenham, UK: Nelson Thornes)