Abstract
Proposals for establishing or changing health care services are increasingly expected to include a framework for evaluating their delivery and effectiveness. Evaluation research in health care is therefore a rapidly developing area. It is crucial that nurses understand how to use this methodology effectively so they can make a case for the establishment, continuation or expansion of a health service and improve existing ones. This article describes aspects of evaluation research as interpreted by Katherine Nelson (RN, MA, PhD) in interview. It is the sixteenth article in a series based on interviews with nursing and midwifery researchers, and is primarily designed to offer the new researcher a first-hand account of the experience of using research methodologies. Kathy is a lecturer in the Graduate School of Nursing, Midwifery & Health at Victoria University of Wellington. She has undertaken several research projects evaluating different health care programmes.

Keywords
Research, methodologies, evaluation, health care

Introduction
Health care systems are developed to provide services that make a positive difference to health outcomes for populations. In New Zealand, ‘health reforms’ have led to continual change of these systems. To ensure people have access to services that are clinically effective, appropriate, safe, timely, cost-effective and delivered in a way that is satisfactory to the person using them, formal and systematic evaluations must be undertaken. The changes have been demanding on nurses in various areas of practice but they have also created opportunities for expansion and advancement of nursing practice, particularly through the development of nurseled services. Regardless of their practice setting or level of experience, nurses need to be aware of the importance of evaluating all aspects of health services. Increasingly nurses are involved in evaluations of their practice area, service or organisation. In the current climate of evidence-based practice they may also be required to evaluate their own practice and would need to use a framework based on the evaluation methodology. Understanding the intention, principles and processes of this research approach is therefore critical to the development of nursing and the effective delivery of all health services. While some writers initially regarded this methodology as relating particularly to the implementation and effectiveness of government policy (e.g. Vedung, 1997), the focus has now broadened to considering the impact of policy-making at all levels including delivery of a service. This postpositivist methodology (Davidson, 2005) can be adapted to evaluate programmes of any size, whether focusing on the practice of an individual, cont.