4. Quality improvement approaches


So far this guide has looked at what is meant by quality and quality improvement, and where quality improvement has come from. This section looks at the theory in practice, identifying some of the best-known approaches to quality improvement. No one approach is better than the others, and some may be used simultaneously.

Business process reengineering

This approach involves a fundamental rethinking of how an organisation’s central processes are designed, with change driven from the top, by a visionary leader. Organisations are restructured around key processes (defined as activities, or sets of activities) rather than specialist functions. By moving away from traditional silos in this way, organisations can identify waste and become more streamlined.

Experience-based co-design

This is an approach to improving patients’ experience of services, through patients and staff working in partnership to design services or pathways. Data are gathered through in-depth interviews, observations and group discussions and analysed to identify ‘touch points’ – aspects of the service that are emotionally significant. Staff are shown an edited film of patients’ views about their experiences before staff and patients come together in small groups to develop service improvements.


This is a quality management system that draws on the way some Japanese car manufacturers, including Toyota, manage their production processes. The approach focuses on five principles: customer value; managing the value stream; regulating flow of production (to avoid quiet patches and bottlenecks); reducing waste; and using ‘pull’ mechanisms to support flow. Using ‘pull’ means responding to actual demand, rather than allowing the organisational needs to determine production levels.

Model for improvement (including PDSA)

This is an approach to continuous improvement where changes are tested in small cycles that involves planning, doing, studying, acting (PDSA), before returning to planning, and so on. These cycles are linked with three key questions.

  • ‘What are we trying to accomplish?’
  • ‘How will we know that a change is an improvement?’
  • ‘What changes can we make that will result in improvement?’

Each cycle starts with hunches, theories and ideas and helps them evolve into knowledge that can inform action and, ultimately, produce positive outcomes.

Six Sigma

This is a systematic approach to improving products or processes. It focuses first on understanding how an organisation’s customers would define ‘defects’ within its products or services. It then works to reduce factors that customers would define as being critical to quality, drawing on statistical methods to develop standards for variation in quality. Developed within the electronics industry, the approach is now widely used in service industries.

Statistical process control

This approach examines the difference between natural variation (known as ‘common cause variation’) and variation that can be controlled (‘special cause variation’). The approach uses control charts that display boundaries for acceptable variation in a process. Data are collected over time to show whether a process is within control limits in order to detect poor or deteriorating performance and target where improvements are needed.

Theory of constraints

The theory of constraints came from a simple concept similar to the idea that a chain is only as strong as its weakest link. It recognises that movement along a process, or chain of tasks, will only flow at the rate of the task that has the least capacity. The approach involves:

  • identifying the constraint (or bottleneck) in the process and getting the most out of that constraint (since this rate-limiting step determines the system’s throughput, the entire value of the system is represented by what flows through this bottleneck)
  • recognising the impact of mismatches between the variations in demand and variations in capacity at the process constraint.

Total quality management (TQM)

Total quality management, also known as continuous quality improvement, is a management approach that focuses on quality and the role of the people within an organisation to develop changes in culture, processes and practice. Rather than a process, it is a philosophy that is applied to the whole organisation, encompassing factors such as leadership, customer focus, evidence-based decision making and a systematic approach to management and change.

* Other than where specified, this section draws on Boaden R, et al. Quality improvement: theory and practice in healthcare. Coventry: NHS Institute for Innovation and Improvement/University of Manchester Business School, 2008.

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