Rising costs and error-related morbidity and mortality have made quality improvement (QI) methods important tools in modern healthcare. Quality improvement is “an applied science that emphasizes innovation, rapid-cycle testing in the field, and spread in order to generate learning about what changes, and in which contexts, produce improvements.”1 Quality improvement science originated in industry as a means of improving efficiency, safety, and product quality in the manufacturing process. The principles and approaches of QI were introduced into the healthcare setting in the 1980s and have become increasingly applied in multiple patient settings to address a wide range of issues including patient safety, patient flow, care efficiency, and healthcare costs.1 Relevant to the practice of infectious diseases, QI has improved adherence to infection control and antimicrobial stewardship interventions, and improved patient management and outcomes.
The popularity of QI in healthcare has been increasing, and it is important to understand the differences between appropriate applications of QI and clinical research. The primary difference between QI and clinical research is the goal of the project. Clinical research often focuses on specific patient populations and static interventions or on the impact of specific exposures, whereas QI focuses on continuous improvement of the system and involves multiple dynamic interventions over time. However, clinical research and QI may overlap in their purposes. It is possible for clinical research to focus on system improvement, and for new scientific knowledge to be obtained during a QI project, such as effective ways to improve certain measures (e.g., central venous catheter bloodstream infection rates) that can be applied at multiple institutions. Nonetheless, the general goal of clinical research is to advance medical knowledge by focusing on patient-level outcomes, whereas the goal of QI is to improve system-level processes.
Several methods on which to base QI work exist, including Six Sigma, Lean, and the Model for Improvement. Six Sigma, focused on reducing variability in production, and Lean improvement methods, focused on reducing non-value-added activities through continuous improvement, developed out of work in the Motorola and Toyota corporations, respectively, and gained popularity in the 1980s and 1990s.2 The Model for Improvement is based on foundational work in manufacturing process improvement championed by engineer and physicist Walter Shewhart at Bell Telephone Laboratories in the 1920s and later by engineer W. Edwards Deming.3 These methods each have conceptually different purposes thus, when utilized, it is important for the QI team to articulate their intended goal on how they want the system to change. However, these methods share common features, including (1) origin in the manufacturing industry; (2) focus on continuous improvement, standardization, and reducing waste in systems; and (3) use of displaying data over time. For the purposes of this chapter, we will focus on the Model for Improvement,2 the framework used by the Institute for Healthcare Improvement (IHI).1