To use systems theory to identify client needs, you need to assess your clients and their systems holistically and comprehensively. Gathering information about the characteristics and functions of the system, such as its size, structure, composition, culture, values, goals, roles, rules, communication, and relationships; the problems and challenges that the system faces; the strengths and resources that the system has; the interactions and influences that the system has with other systems; and the changes and adaptations that the system has made or needs to make is essential. To do this, you can use different tools and methods such as interviews, observations, questionnaires, genograms, ecomaps, or life histories. Additionally, different theoretical perspectives and models can guide your assessment like ecological systems theory, family systems theory, or empowerment theory.