Books Textbook Review

Quality Improvement Tools & Techniques

For those of you in the operations research side of the medical care world, you may recognize an interesting textbook by Peter Mears title Quality Improvement Tools and Techniques. The book is a good reference tool, but is a little difficult to slug through. It has so many graphs, outlines, quotations, that there is little room for text. The book gives classic B-school tools such as: a fishbone diagram, deployment charts, focus groups, benchmarking and customer needs mapping. For those with little statistical background, the book also explains in a simple, concise fashion how to construct pie and bar charts, histograms, radar charts, pareto diagrams and control charts. The book is somewhat out of date in that it does not give detailed explanations of how to perform these actions in a statistical program such as Excel.


Quality is a key component of customer (or patient) satisfaction with any service or product. In medical care, measuring quality is even more difficult than in other fields. There are three types of quality:

  • Perceived Quality: This is the customer’s (patient’s) personal belief as to the quality they receive.
  • Actual Quality: This is often measured by some quantitative metric (e.g.: defects per 100, number of breakdowns, ease of use). In the medical world, finding relevant metrics to measure performance is difficult. Often we can measure the amount of medical errors per 100 patients a physician makes, but this will not measure superior physician quality. Peer review is one way to measure actual quality, but since this is often done in a non-quantitative way, even most medical professionals are uncertain of quality of care they give.
  • Expected Quality: This is the quality level a customer expects. This is often influenced by marketing and word-of-mouth information. An example of differences in expected quality would be that someone with top notch health insurance coverage would likely expect a professional, sleek, expensive office setting in the San Diego area. If the same person had no health insurance and decided to go to Tijuana for medical care, their expected quality of care would likely be lower.

Taguchi Methods

Dr. Genichi Taguchi is a Japanese statistician and Deming Prize winner who has introduced a novel quality control system. Below I point out some of the highlights.

  1. Quality is measure by the total loss to society. What is the total loss to society? It contains 2 parts. First there is the cost to manufacture or provide the good to the consumer. Second, there is the cost of inferior quality. In the healthcare setting, simply reducing financial costs will be unsatisfying under the Taguchi methodology if quality of care is not at the same time maintained or improved.
  2. Continuous Quality Improvement and Cost Reduction are necessary. Did you hear that economists? Most economists analyze a problem in a fairly static setting. Technology parameters are taken as given and economists are able to derive an optimal solution for a given problem. This answer is less satisfying if you know that your parameter assumptions are relevant only in the very short run. Economists such as Schumpter and his notion of creative destruction are able to incorporate a ‘continuous improvement’ framework in their economic analysis.
  3. Quality improvement involves reducing variation. It is important to have a quality product all the time. This is done by reducing variation (e.g.: 6σ methodologies). This precept is very difficult to apply to medical care because of patient heterogeneity.
  4. Product and Process Design have a strong impact on quality. In service sectors, often product and process design are one and the same.