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Putting prevention into practice (Green Book)

Plan, do, study, act cycle

The 'plan, do, study, act' (PDSA) cycle (Figure 4) uses simple measurements to monitor the effects of change over time. It encourages starting with small changes, which can be built into larger improvements quickly, through successive cycles of change. It emphasises starting unambitiously, reflecting and building on learning. It can be used to test suggestions for improvement quickly and easily based on existing ideas and research, or through practical ideas that have been proven to work elsewhere.

Figure 4. PDSA cycle

Figure 4. PDSA cycle

Plan the change (P)

  • What do you want to achieve, what actions need to happen and in what order?
  • Who will be responsible for each step and when will it be completed?
  • What resources are required?
  • Who else needs to be kept informed or consulted?
  • How will you measure changes to practice?
  • What would we expect to see as a result of this change?
  • What data do we need to collect to check the outcome of the change?
  • How will we know whether the change has worked or not?

Do the change (D)

Put the plan into practice and test the change by collecting the data. It is important that the ‘do’ stage is kept as short as possible, although there may be some changes that can only be measured over longer periods. Record any unexpected events, problems and other observations.

Study (S)

  • Has there been an improvement?
  • Did your expectations match what really happened?
  • What could be done differently?

Act on the results (A)

Make any necessary adaptations or improvements, acknowledge and celebrate successes. Collect data again after considering what worked and what did not. Carry out an amended version of what happened during the ‘do’ stage and measure any differences.

Applying the PDSA cycle – identifying patients with heart disease


Cycle 1

Cycle 2


The team decides to identify CHD patients through repeat prescription requests by looking for patients receiving nitrates for angina. (Patients usually place their requests in a box on the reception desk) The change they are going to test for is the monitoring of repeat prescriptions The data they are going to collect is the number of patients on nitrate prescriptions The reception desk box will be replaced with a notice saying that patients should hand their requests to a receptionist The receptionist will look at the items on the prescription requests to identify any nitrate prescriptions (a list of drug names will be printed out and stuck on the wall in reception) The names of patients on nitrates will be noted on a form kept under the reception desk. This will be done for 1 week, after which the numbers of patients identified will be counted

The practice nurses (PNs) decide to use a quick checklist when using the notes to identify patients with CHD PNs agree to look for the following when reviewing the notes: CHD diagnosis, a history of myocardial infarction or angina or high blood pressure The PNs agree to review five sets of notes each per day for 2 days PNs decide to see how easy it was to get the information by measuring how long it took to go through each set of notes



The repeat prescription box was removed and a simple form produced to record patient names A notice was put up asking patients to hand in their repeat requests to reception staff

The PNs divide the notes between each other and use a checklist to record patients who fulfil the inclusion criteria


After 1 week, 22 patients on nitrates had been identified and their names recorded The receptionists had no difficulties scanning the repeat requests, even during busy times, but had noticed that two drug names were missing from their list. They also thought it would be a good idea to record patients’ birth dates as some patients had the same name

The PNs found there was variation, ranging from 30 seconds to 5 minutes, in the time it took to go through the notes Two of the PNs found no problem going through five sets of notes during a working day, but the part-time nurse found it difficult to get through her notes in the time allowed. The PNs agreed that when going through the records, it would also be useful to check if the patient had had a cholesterol check in the previous 2 years


After discussion, it was decided to:

• continue identifying CHD patients and their date of birth for another month and then study the results again
• update the list of nitrates to include all relevant drug names
• increase the size of the print on the notice about the repeat prescription box
• begin a new PDSA cycle and for the PNs to check the notes of those patients identified in order to confirm they have CHD

Shiong Tan, Perth, Western Australia

The part time PN reduced the number of notes reviewed each day Cholesterol checks were added to the list of markers for CHD The next PDSA cycle could address how to capture new diagnoses for the developing CHD register by using a checklist that administrative staff could use. The PDSA cycle could then address the percentage of patients on the current CHD register who took a particular medication and could document the need for review

Cycles of improvement may occur at different levels and new actions may be planned as a result of previous cycles. Alternatively, new skills may be learned, barriers to change overcome and new areas targeted for improvement. Testing small changes sequentially means design problems may be detected and amended earlier rather than later. Similarly, performance tends to fall away with time. Repeated measurement of both process and outcomes helps to identify current performance and any areas of concern.45 Self assessment of performance, while necessary, often overestimates performance and may not be either accurate or sufficient.46 When reviewing your progress:

  • check that your goals have been achieved
  • decide if the goals have been realistic
  • see if the energy invested has led to the desired degree of change. Is the return worth the effort?
  • document which factors have helped or hindered the change
  • are there any further strategies or measures needed to bring about the desired changes and/or improve cost effectiveness?