a four-step improvement cycle for organizing and managing change and continuous improvement. The cycle is used for incremental improvements as opposed to benchmarking when radical changes are called for (Conyers and Ewy, p. 62). This cycle was developed by Dr. Walter Shewhart in the 1920s and put into business practice in Japan and the United States by W. Edwards Deming. (Embedded in the PDSA cycle are quality tools to facilitate the process.) The four steps are defined, as follows: In the Plan phase, the specific change or problem is defined through root-cause analysis and a plan is designed to address the problem or desired change. In the Do phase, the improvements to be made are deployed through the development of action plans. Frequent monitoring allows for rapid response to change the course, if needed. In the Study phase, formative data measures are monitored and analyzed to see if the improvement is producing the desired change. In the Act phase, a decision is made as to whether the results have created the desired change for standardization or if more improvement is needed, in which case, the PDSA cycle starts all over again.

Plan, Do, Study, Act, (see Shewhart Cycle) - A method for learning and for improvement. Also described as Plan, Try, Observe, Act (on observations). Popularized in Japan as Plan, Do, Check, Act, or PDCA. Deming prefers study rather than check in order to emphasize the importance of learning in improvement.

PDSA is a veterinary charity in the United Kingdom. It was founded as People's Dispensary for Sick Animals in 1917 by Maria Dickin to provide care for sick and injured animals of the poor. It is the UK's leading veterinary charity, carrying out more than one million free veterinary consultations a year, and is the largest private employer of fully qualified veterinary surgeons and veterinary nurses in the UK.