A social worker must have a variety of knowledge and understanding of theories when working with individuals. I will begin the essay by examining what theory is and the nature of the relationship between theory and practice. I will discuss two specific theories, namely Cognitive Behavioral Therapist (CBT) and Person Centered Approach. As I explain the theories I will identify their underlying values ​​and explain how they might support or even conflict with social work values. C. Becket DATE explains how social work practice is extremely diverse in many ways. There are a number of service user groups that social workers work with. Some of these include children and families, young offenders, seniors, adults and children with mental health issues. Some social workers may be dedicated to a particular area, however they will need to have a systematic understanding of the theories to be able to work effectively with all groups of service users. I will discuss how the theories will be applied to older people. The purpose of social work is to improve the conditions of society. It can be very challenging, however, structures are acquired to be able to provide solutions (Greene 2008). The theories provide goals to support social workers to help people improve their social situation. There are several theories that explain human behavior and the factors that influence it (Howe 2009). Theories such as psychodynamic theory view human behavior as childhood experiences, however, behavioral theory views it as actions that lead to positive behavior. Carl Rogers (1902-1987) was the inspiring founder of the theory of person-centered care. Hall and Scragg (2012) argue that, from a person-centred perspective, services for older people are adequate and must carefully consider planning to meet their needs. It is important that the needs of older people are met and that attention is focused on them throughout the intervention. It is important to inform them fully. The national regulatory framework for older people sets standards to ensure that services respond effectively to the needs of individuals in social work practice. This is done through appropriate planning, evaluation, intervention, monitoring and review. Historically, the evaluation process has not been very clear in social work, which can cause a lack of precision. Therefore social work focuses more on explaining intervention methods rather than evaluation models. Sinclair et al (1995) explained that evaluation usually occurs when a problem is identified, the purpose of which a solution is found.