The plethora of new models being used in healthcare for everything from information systems to workflow improvement processes led to the selection of "models" as the theme of this issue. But it soon became apparent that the main theme of the issue is change. Models are tools for change. Interest in models reflects the rapid growth and change in the healthcare system. The previously homogeneous healthcare system is now heterogeneous. Models allow the development of new products and processes that can be adapted to complex, diverse systems that characterize healthcare today. Because models are developed from variables and the relationships among them, they provide an intelligent way to design products and processes shaped to fit various situations and to manage change.

Nurse executives have used patient care delivery and nursing practice models for decades. They now deal with models in almost every aspect of healthcare from information systems, financial processes, systems and workflow improvements, architectural design, and other areas. Many executives have their favored models. Evaluating these models to ensure that they fit the organization has become an executive challenge for many reasons. As healthcare moves toward integrated, multidisciplinary, patient-centric services, models formerly relegated to 1 function are now integrated and contain aspects of many functions. Most central to nursing are the models that deal with nursing practice and care delivery. Evolution of these models has led to multiple definitions, complexity, and confusion about what should be in the model, how it should be structured, and how it applies to the real world of patient care. It is helpful to step back and examine change and the use of models in change.

Models are useful to explain how systems are structured and how they work. Nurses are most accustomed to using the abstract models that are theoretical constructs of nursing practice and care delivery, usually based on nursing principles and theories. There are multiple types of models in use today. Much of healthcare is organized in systems. For example, there are systems for quality improvement that use causal models to aid understanding of processes and to help redesign and improve those processes. Another example is the information system with potential to integrate organizational resources in a complete system that tracks the cost of providing patient care, clinical processes, and measurable outcomes. Different types of models are used to fit the purpose. There are metalevel models that contain generic concepts, process models that depict a way of working, and developmental models that allow the evaluation of what happens if variables are related in certain ways. The plethora of models we now have is available because of technology. Software allows even amateur modelers to enter their variables and run programs to determine the results.

As tools, models are useful to help nurse executives design and manage change to improve patient care. In this issue, content was selected to provide a perspective of change in nursing, of new models being idealized or developed and tested, and of the change process, particularly business case development and nurse executive competencies. Some readers may want to explore the science of developing and using models, which will probably become a curriculum thread in graduate education in the future. For those readers, Wikipedia (http://en.wikipedia.org/wiki/Model), the free encyclopedia, provides a provocative and interesting starting place.

We live in a world of systems driven by cause and effect. Modeling provides a way to understand how a system really works and how to use the system, improve it, automate it, or explain it to others. This special issue of Journal of Nursing Administration was designed for the nurse executive who is meeting the challenges of change in today's world. The issue begins with Vlasses and Smeltzer's article about the forces of change and projections of future healthcare systems, with examples of initiatives already underway to dramatically change healthcare delivery. Wolf and Greenhouse follow up with a discussion about the expanding models for patient care delivery. A nurse executive's perspective of the inevitable change and emerging models of care delivery is then presented by Reineck. The next 2 articles provide rich content about the research on emerging care delivery models, written by Kimball, Joynt, Cherner, and O'Neil, and the nurse executive's role in implementing these new models, written by Morjikian, Kinball, and Joynt. The complexities of change are then presented by MacPhee, with tools for change that have been proven to be effective over time. The final article in this issue by Weaver and Sorrell-Jones is a clear description of how to develop and present a business case that makes the idealized design a reality.

Change happens. Effective nurse executives design the change, manage it, and evaluate the results. Sometimes change can be focused on 1 process or 1 aspect of patient care. Other times, it can be focused on broader processes or systems. Each organization has its own history, its own current situation, and community and employee expectations. What is major change for one organization may be an accomplished fact in another. Perceptions of change may be situational, and the extent of change can be varied. In any situation, changes, large or small, are major in people's lives. The nurse executive is mindful of the effects of change and the knowledge that all changes, large or small, are part of the journey toward the future.