Tools for total quality management 9 Tools for total quality management Contents Introduction ............................................................................................................... 9–3 Essential readings ...................................................................................................... 9–3 Objectives .................................................................................................................. 9–4 In your experience ..................................................................................................... 9–4 Total quality management tools ................................................................................ 9–4 Pareto Charts ......................................................................................................... 9–4 Ishikawa Diagrams (also known as Cause and Effect Diagrams and Fishbone Diagrams) .............................................................................................................. 9–5 Check Sheets ......................................................................................................... 9–5 Histograms ............................................................................................................ 9–6 Scatter Diagrams ................................................................................................... 9–6 Run Charts & Control Charts ................................................................................ 9–7 Stratification .............................................................................................................. 9–7 The role of management ............................................................................................ 9–8 Conclusion ................................................................................................................. 9–8 Further reading ...................................................................................................... 9–9 References ................................................................................................................. 9–9 Review questions ....................................................................................................... 9–9 Further questions ................................................................................................. 9–10 9–2 Tools for total quality management Introduction There are a number of tools commonly used in organisations that have implemented total quality management. Many of these are covered in this module. The main purpose of these tools is (a) to be able to measure quality; and (b) for these measurements to be performed by the people doing the job. This is why the tools tend to be straightforward to use, do not require complex calculations or statistics, and allow graphical presentation of information. Often sophisticated data that can be produced using fairly simple methods, and which can be presented in a manner which makes the outputs meaningful. This module includes Pareto Charts, Ishikawa Diagrams, Check Sheets, Histograms, Scatter Diagrams, Run Charts and Control Charts. It also involves examining the concept of stratification and the role of management with regard to the deployment of total quality management tools. Essential readings Textbook Goetsch & Davis 2006 Ch. 15. Overview of Total Quality Tools. Electronic journal article Hedley, M 2005, ‘Curse of the Super-fish-al’, Quality Progress, vol. 38, iss. 7. (Search ProQuest using the Library’s electronic resources page) Electronic journal article Bothe, DR 2001, ‘Use check sheets to identify the causes of downtime’, Quality Progress, vol. 34, iss. 4. (Search ProQuest using the Library’s electronic resources page) Electronic journal article Gerst, R 2003, ‘Control charts in the comptrollers office (and other peculiar places)’, Quality Congress, ASQ’s Annual Quality Congress Proceedings, vol. 57. (Search ProQuest using the Library’s electronic resources page) 9–3 Tools for total quality management Objectives On completion of this module you should be able to: 1. identify common total quality management tools 2. describe the use of the following tools Pareto Charts Ishikawa Diagrams (also known as Cause and Effect Diagrams and Fishbone Diagrams) Check Sheets Histograms Scatter Diagrams Run Charts Control Charts. 3. explain how stratification can be used to create meaning through categorising 4. describe the role of management with regard to the deployment of tools. In your experience Many systems are used to keep track of a range of activities. These include cash register roles that keep track of every transaction registered; odometers that keep track of kilometres or miles travelled by a car; and timesheets people use to keep track of (and request payment for) work they perform. What systems are you aware of that you or other people use to keep track of time, effort, resources, etc.? Total quality management tools Pareto Charts The Pareto Principle states that ‘in the real world a minority of causes leads to the majority of problems’ (Goetsch & Davis 2006, p. 352); or more generally ‘that in many instances a small proportion of items account for a large percentage of some variable linked to those items’ (Rao et al. 1996, p. 181). Pareto charts are simply bar charts that allow the larger contributors to a factor to be easily identified (such as Figure 15–1 in Goetsch and Davis 2006, p. 353), that shows percentage of total sales by customer. ‘Digging deeper’ is always an important method of analysing information. Goetsch and Davis (2006) present cascading Pareto charts as a method of analysing successively more basic data without becoming overwhelmed with detail, by dropping the 80% of data at each level. 9–4 Tools for total quality management Ishikawa Diagrams (also known as Cause and Effect Diagrams and Fishbone Diagrams) Dr Kaoru Ishikawa pioneered a simple method of presenting information, grouping logically related information, and (as noted above) digging deeper to find causes of problems that can be perceived. The method involves a visual representation called an ‘Ishikawa diagram’. This is also known as a cause and effect diagram or a fishbone diagram. The diagram is simply a way of grouping the possible causes of problems in terms of major influencing factors and (grouped under these) minor influencing factors to whatever level is appropriate. The diagram is typically developed by a group with an understanding of different aspects of the problem, and is used to organise the often chaotic mass of information that comes out of brainstorming about the problem. There will frequently be ‘generic’ influencing factors that allow speedy identification of initial categories, such as people, plant and equipment, policies and procedures in dealing with problems with administrative processes (Rao et al. 1996). The diagram does not produce the answer, but gives those seeking a solution a better understanding of the problem, which should assist in further investigation. The electronic journal article by Hedley (2005) goes further by indicating how superficial use of Ishikawa diagrams is a waste of time, and indicating how they can be used to be a powerful tool for problem solving. Check Sheets A simple method of keeping track is to make a check mark each time something happens (or did not happen). The layout of the space in which the check marks are placed is very important. The manager of a sheep station wants to know how many sheep need to be yarded (brought from the paddock and put into the yard beside the shearing shed) before the morning session of shearing, and how many before the afternoon session. The manager can only find this out from the previous day’s tally sheet if the tally shows how many sheep were sheared in the morning, and separately how many sheep were sheared in the afternoon. If the same manager were paying each shearer by the sheep, and wanted to know how much to pay each shearer, the tally sheet would need to also be divided up by shearers. 9–5 Tools for total quality management An example of such a tally sheet is below. Shearing Tally Sheet for: 25 November Completed by: Julie Shed number: 3 Morning Afternoon TOTAL Bill 25 Sheryl 23 Arthur 18 Ashley 13 TOTAL 43 36 79 The electronic journal article by Bothe (2001) provides two examples of check sheets in use at a shipbuilding yard. Goetsch and Davis (2006) note that where possible the check sheet should be completed by the person doing the work and that where possible no complicated statistical analysis should be required. Histograms Histograms are relatively straightforward, as long as you are aware that you need to know what sort of information you are looking for before constructing the graph, so you know how to represent the data. In many cases all that will be done is that the histogram will be used to find peaks, troughs and outliers. In some cases, more statistical examination will be required, including calculating the mean, standard deviation and other variables. Scatter Diagrams Scatter diagrams allow measures of two variables to be compared. Statistical analysis can be used for an indication of ‘how well’ things correlate or do not correlate. In many cases, a simple visual examination is sufficient to see whether a correlation exists, and whether the correlation is negative or positive. (Note: For those people unfamiliar with the measure miles per gallon in Goetsch & Davis (2006, p. 372), Figure 15–22 more miles per gallon is ‘better’ than less miles per gallon, so the slower the cars went, the better the fuel consumption, except that at very slow speeds (20 to 30 miles per hour) the opposite applied for three out of the four cars.) 9–6 Tools for total quality management Run Charts & Control Charts Run charts provide a simple visual representation of activity over time. Control charts are a more sophisticated run chart that comprises additional information in the form of upper and lower control limits (to show tolerances) and a process average over a longer period of time than that represented at each point on the chart. These are more valuable than run charts, in that it is possible to tell whether the activity being shown on the chart meets the tolerances you have set, and whether the activity line is straying above or below the average. The electronic journal article by Gerst (2003) is about how Run Charts and Control Charts are used to demonstrate performance beyond the typical quality management applications (although certainly in keeping with their intent to assist in managing quality). Interestingly, the article goes further, by demonstrating the use of a further tool, the digital dashboard. Stratification As explained in Goetsch and Davis (2006), stratification is a simple process of dividing up data in order to find something out about the data. In the case of the manager of the sheep station (above), 8 sheep (or about 10% of the total sheep) had cuts that required stitching. The manager was not happy about this, and set out to find out more. On the first day, the only information he had was in the tally sheet below. Injuries (to Sheep) Tally Sheet for: 25 November Completed by: Julie Shed number: 3 Morning Afternoon TOTAL Nicks (bleeding, no stitching required) 9 Cuts (bleeding, stitching required) 8 No injury 62 TOTAL 43 36 79 9–7 Tools for total quality management The next day the manager asked Julie (the Counter) to keep a tally of cuts by shearer. He did not need detailed data for nicks and no injury, as these were not important to the information he was looking for. He wanted to know whether the cuts were spread evenly among the shearers. The result of this new tally would be information about who was doing the cuts. The resulting tally sheet is shown below. Injuries (to Sheep)—cuts only Tally Sheet for: 26 November Completed by: Julie Shed number: 3 Cuts (bleeding, stitching required) TOTAL Bill 2 Sheryl 2 Arthur 3 Ashley 3 TOTAL 10 10 The final tally sheet shows that all of the shearers are cutting sheep, with Bill and Sheryl cutting the most. However, given that Arthur and Ashley shear less sheep than Bill and Sheryl, the ratio of cuts to sheep sheared might be pretty even. (Note: Given the small sample size, caution should be exercised attributing any meaning to these figures.) Similarly to the sheep station manager’s problem above, the electronic journal article by Bothe (2001) provides a worked example from a shipbuilding yard, in which again check sheets and stratification were used to address an important issue. The role of management Goetsch and Davis (2006) recognise that management’s role in many cases is to provide resources and get out of the way, enabling employees to get on with what they know needs to be done to improve processes and outputs. This is only going to be effective if empowerment (covered in an earlier module) has been achieved. Management is still responsible for facilitation, providing resources, monitoring activity at a strategic level, and ensuring the long-term viability of the organisation by encouraging product improvement and new product identification and development. Conclusion This module is much more intensive in terms of detail and practical application than the previous modules. It is about investigating problems and resolving them, and (to a lesser extent) identifying opportunities and exploiting them. 9–8 Tools for total quality management Further reading The recording of data of this type is outlined in the book: Goldratt, EM 1997, Critical chain, North River Press, Great Barrington. Goldratt demonstrates how simple measures can be used to better understand the causes of problems in a manufacturing environment. The book also illustrates the role of management in supporting staff and providing the resources and motivation to seek out and resolve issues. References Goetsch, DL & Davis, SB 2006, Quality management: introduction to total quality management for production, processing, and services, 3rd edn, Pearson Prentice Hall, Upper Saddle River, NJ. Rao, A, Carr, LP, Dambolena, I, Kopp, RJ, Martin, J, Rafii, F & Schlesinger, PF 1996, Total quality management: a cross functional perspective, John Wiley & Sons, New York. Review questions Review question 9–1 Complete ‘Discussion assignment 15–1’ in Goetsch and Davis (2006, p. 397). Consider the suggestions you could make to the president regarding measures that could be commenced to provide meaningful information, and explain how the Ishikawa diagram could be used to identify potential causes of the defects. Review question 9–2 A person worked in a warehouse for a period of time, and was fascinated by the effectiveness of a simple technique of tracking products on shelves. When items were delivered a ribbon of paper was fastened to the end of the shelf with the number of items delivered at the top. As one or more items were removed, the person removing the items would mentally subtract the number they took from the number on the ribbon of paper, cross out the old total and write down the new total. The author’s task of doing a fortnightly check of available stock was considerably easier due to the ribbons. The ribbon of paper held useful information. Not only could a person immediately see how many items of a product line remained on the shelf, by presenting the fortnightly data on a graph, demand could be quickly seen across a set timeframe. A knowledge of seasons and other influencers of purchasers can make the peaks and troughs more meaningful. The purchasing department could assess required inventory levels based on seasonal demand. The warehouse manager could maximise the use of available shelf space by examining peaks on the graph. The sales manager could see whether volume discounts could be offered to customers without disappointing them by being unable to deliver sufficient products. All of this from a list of numbers on a ribbon of paper. Your task is to describe how the ribbon of paper could have been replaced by a check sheet to make the information being collected more immediately meaningful. 9–9 Tools for total quality management Review question 9–3 You are the manager of a restaurant which is being re-modelled. The architect has asked you how many people you need to be able to seat in the upstairs area which will only be open in the evening, and how many people you need to be able to seat downstairs which will be open for both lunches and dinners. You currently have only one area, which is used for lunches and dinners, although is often partially empty at lunchtime. You have a fortnight to give an answer to the architect. What can you do to obtain realistic figures? Further questions The Factual Review Questions and Critical Thinking Activities in your textbook are useful for refreshing your knowledge. You may like to consider these now, or as part of your examination preparation. The Critical Thinking Activities give you an opportunity to test your understanding of the tools in the chapter. The activities that involve ‘Selecting Improvement Subjects Using Pareto Charts and Stratification’ and ‘Constructing a Cause and Effect Diagram’ are particularly useful. 9–10