In all schools of thought, people have developed different systems to help approach questions that humanity faces. Theories are abstract models that are aimed at explaining real-world phenomena. This way of looking at the world provides people with a set of tools and frameworks for analysis. Although this method is useful, it has a set of limitations. All theories by their nature simplify reality and only focus on specific aspects of a phenomenon. Thus, different models have different accuracy, and it is important to have a method for evaluation that shows how well a particular theory serves its purpose. The goal of this paper is to discuss the criteria of theory evaluation and use them to analyze a grand nursing theory. The set of criteria that scientists use to test a theory consists of the following items: empirical and pragmatic adequacy, utility, logical consistency, testability, and scope. In addition to that, it is also essential to assess in how much detail the model covers the phenomenon, and to what extent it stimulates new research (Smith and Parker 31). This framework can be used to critique and analyze theories in nursing. Grand nursing theories are very broad, and they deal with questions at a high level of abstraction. They provide a conceptual framework that focuses on large domains of nursing and is large in scope (Reed and Nelma 8). The self-care deficit approach that was developed in the second part of the twentieth century is a good example of such a theory. The philosophy of this model is based on the fact that people adapt to their environment and have a natural strive to be able to care for themselves (Smith and Parker 108). The theory emphasizes that patients can recover faster if they perform self-care as well as they can and only rely on outside help and treatments when it is necessary. The self-care deficit theory can be analyzed with the help of the mentioned criteria. The model covers a broad scope of nursing practices and can be applied in most branches of medicine. The approach is proved to be especially useful in primary care and rehabilitation, where patients’ contribution to the success of the treatment is especially big. Multiple controlled trials proved the utility and empirical adequacy of this model, showing that such an approach leads to improved quality of care (Smith and Parker 110). The high level of testability of the model allows evaluating it with measurable and reliable results (Smith and Parker 110). The theory is also pragmatic because the vision it provides is highly applicable and can be used to deal with real situations in medicine. In addition to that, the theoretical framework of this model provides a perspective and a set of tools that can be used by future researchers, including both theorists and practitioners. Thus, having evaluated the self-care deficit theory, it is justified to say that this model is accurate, testable, and can be applied to improve the quality of care in medical institutions. Grand nursing theories provide abstract models and frameworks that are aimed at helping develop practical approaches to real-life medical situations and solve problems that appear in the hospital environment. Evaluating these theories is necessary to determine their practical applicability, accu