Few problems fall solely into one design discipline’s skillset. The lines between them are blurry. For example, even a basic user interface problem has elements of communication design and experience design. Most designers are comfortable in more than just one area. Just like medical doctors, designers tend to go through some common training (like visual thinking for example), then they hone their skills further and specialize in certain areas over others.
Since you have selected Systems here is some further information on the design skillsets that may be needed in this category.
System Design or System Innovation is an approach to understand how innovations at different levels of a system, from the macro to the micro, come together to drive transition. It focuses on the role of purpose, power, relationships and resources in unlocking systemic change, and the cast of actors involved in making deliberate system change happen.
Strategic design is the application of future-oriented design principles in order to increase an organization’s innovative and competitive qualities. This design discipline is about applying some of the principles of traditional design to “big picture” systemic challenges. It redefines how problems are approached, identifies opportunities for action, and helps deliver more complete and resilient solutions.
Participatory design is an approach that invites stakeholders such as clients, users, and community members into the design process to ensure that a design meets the needs of those it is serving. It is a type of social research in which the people being studied have significant control over participation, collaboration, and agency. Design work is inherently participatory in nature, and the notion of participatory design is often used to call out the need to increase buy-in and ownership when developing health solutions for users and providers who may lack a sense of control and agency within the broader health system.