AIG Seven QC Tools
- 2. Contents Overview Introduction to Minitab Histograms Pareto Chart Cause and Effect Diagram Flow Chart Scatter Diagrams Control Chart Check Sheet +1 Box Plot
- 3. The term “7 tools for QC” is named after the 7 tools of the famous warrior, Benkei. Benkei owned 7 weapons, which he used to win all his battles. Similarly, from my own experience, you will find that you will be able to solve 95% of the problems around you if you wisely use the 7 tools of QC.” - Ishikawa The 7 QC Tools are proven scientific management tools, which are basic and easy to understand. They form the fundamental foundation for all problem solving and quality control activities. Benefits Provide Training in Thinking Raise People’s problems Solving Confidence Increase People’s ability to predict future Events Overview
- 4. Minitab is a general purpose statistical package designed for easy interactive use. Minitab was originally designed as a tool to be used in teaching statistics. Its interactive features make it well suited to instructional applications, and Minitab's greatest popularity remains as a teaching tool. However, Minitab is sufficiently powerful that it is also used by many people in analyzing research data. Minitab - Introduction
- 5. Histogram Histograms provide a simple, graphical view of data, including its dispersion and central tendency. In addition to the ease with which they can be constructed, histograms provide the easiest way to evaluate the distribution of data. Histograms in Minitab. Put data into column Path Stats > Descriptive Stats > Click Data into variables > Graphs > Histogram > Click OK > Get Results. Maximum mortality rate remains between 12.5% to 17.5%.
- 6. Pareto Chart Pareto charts are extremely useful because they can be used to identify those factors that have the greatest cumulative effect on the system, and thus screen out the less significant factors in an analysis. Ideally, this allows the user to focus attention on a few important factors in a process. Pareto on RHS shows that Cataract services are performing best (59%) in their area . Data - > Put Data in two columns. One columns should have nos. the other column should have some for those reasons. Path- Stats -> Quality Tools -> Click defects table Put reasons in Labels and Data in Frequencies. > Click OK - > Get Result
- 7. Cause and Effect Diagram This diagram, also called an Ishikawa diagram (or fish bone diagram), is used to associate multiple possible causes with a single effect. Thus, given a particular effect, the diagram is constructed to identify and organize possible causes for it. A typical Fishbone has been shown in the picture. Generic Model – 6 Ms Management Mother Nature Methods Material Men Measurement
- 8. Flowchart Flowcharts are pictorial representations of a process. By breaking the process down into its constituent steps, flowcharts can be useful in identifying where errors are likely to be found in the system. A typical Flow Chart diagram has been shown in the diagram for improving Visual Acuity
- 9. Scatter Diagram Scatter diagrams are graphical tools that attempt to depict the influence that one variable has on another. A common diagram of this type usually displays points representing the observed value of one variable corresponding to the value of another variable. This region shows that there is a positive correlation between Follow ups with Patients and Visual Acuity Scatter plots in Minitab. Put the data of variables in two columns, Path ->Graph > Scatter plot > (With Connect Line) > Ok > Fill Y variables and X variables > Ok > Get Result With high no. of follow ups there is no effect on VA
- 10. Control (P) Chart The control chart is the fundamental tool of statistical process control, as it indicates the range of variability that is built into a system (known as common cause variation). Thus, it helps determine whether or not a process is operating consistently or if a special cause has occurred to change the process mean or variance. The bounds of the control chart are marked by upper and lower control limits Outliers are giving opportunity to work on Patient Satisfaction score. Control Charts in Minitab. Put Data in column of Satisfaction Score. Path -> Stats > Control Charts > Attribute Charts > P Chart
- 11. Box plot Box plot is a graphical representation of performance in 4 quartiles. Thus lets us know where is the current median performance of the process. In the given example, 75 % times it has happened that Patients who have SEVERE ROP and have undergone Cryotherapy have visual acuity between 0.7 and 0.3 Box plots in Minitab. Put Data in column. Path -> Graph > Box Plot > Simple y or Simple Y with Groups. > Put Data in Variable box > OK> Get Results
- 12. Checksheet The function of a check sheet is to present information in an efficient, graphical format. This may be accomplished with a simple listing of items. However, the utility of the check sheet may be significantly enhanced, in some instances, by incorporating a depiction of the system under analysis into the form. Check Sheet Example The figure below shows a check sheet used to collect data on telephone interruptions. The tick marks were added as data was collected over several weeks.
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