miercuri, 1 februarie 2012

12. The Tools of Quality Management

The need for the tools of quality: Improving the system. The business must balance the needs of the basic functional areas: Marketing, Accounting, Human Resources, Operations, Engineering, Strategy.

Ishikawa’s basic seven tools of quality: Process maps, Check sheets, Histograms, Scatter plots, Control charts, Cause and effect diagrams, Pareto analysis.

Process Map: Visually depicts the sequence of events to build a product or produce an outcome. It comprises a stream of activities that transforms a well defined input or set of inputs into a pre-defined set of outputs.

Flowchart: Start and end symbols: represented as ovals or rounded rectangles, usually containing the word "Start" or "End", or another phrase signaling the start or end of a process, such as "submit enquiry" or "receive product". Arrows: showing what's called "flow of control" in computer science. An arrow coming from one symbol and ending at another symbol represents that control passes to the symbol the arrow points to. Processing steps: Represented as rectangles. Examples: "Add 1 to X"; "replace identified part"; "save changes" or similar. Input/Output: Represented as a parallelogram. Examples: Get X from the user; display X. Conditional or decision: represented as a diamond (rhombus). These typically contain a Yes/No question or True/False test. This symbol is unique in that it has two arrows coming out of it, usually from the bottom point and right point, one corresponding to Yes or True, and one corresponding to No or False. The arrows should always be labeled. More than two arrows can be used, but this is normally a clear indicator that a complex decision is being taken, in which case it may need to be broken-down further, or replaced with the "pre-defined process" symbol.

SIPOC diagrams are very easy to complete. Here are the steps you should follow: Create an area that will allow the team to post additions to the SIPOC diagram. This could be a transparency (to be projected by an overhead) made of the provided template, flip charts with headings (S-I-P-O-C) written on each, or headings written on post-it notes posted to a wall. Begin with the Process. Map it in four to five high level steps. Identify the Outputs of this Process. Identify the Customers that will receive the Outputs of this Process. Identify the Inputs required for the Process to function properly. Identify the Suppliers of the Inputs that are required by the Process. Optional: Identify the preliminary requirements of the Customers. This will be verified during a later step of the Six Sigma measurement phase.

Check Sheet: A structured, prepared form for collecting and analyzing data.

Histogram: Representation of a frequency distribution by means of rectangles whose widths represent class intervals and whose areas are proportional to the corresponding frequencies. A bar chart.

Scatter Plots: Show the relationship between two variables by displaying data points on a two dimensional graph. Is useful when there is a large number of data points.

Control Chart: Is used to study how a process changes over time. A control chart always has a central line for the average, an upper line for the upper control limit and a lower line for the lower control limit. These lines are determined from historical data. By comparing current data to these lines, you can draw conclusions about whether the process variation is consistent (in control) or is unpredictable (out of control, affected by special causes of variation).

Out-of-control signals: Obvious consistent or persistent patterns that suggest something unusual about your data and your process. A single point outside the control limits. Two out of three successive points are on the same side of the centerline and farther than 2 σ from it. Four out of five successive points are on the same side of the centerline and farther than 1 σ from it. A run of eight in a row are on the same side of the centerline.

Cause and Effect Diagram: Helps to visually display the many potential causes for a specific problem or effect. It is particularly useful for situations in which little quantitative data is available for analysis.

Pareto Diagram: 20% of sources are causing 80% of the problems (80/20 Rule). Is used to graphically summarize and display the relative importance of the differences between groups of data. The first few contributing causes to a problem usually account for the majority of the result. It answers: What are the largest issues facing our team or business? What 20% of sources are causing 80% of the problems (80/20 Rule)? Where should we focus our efforts to achieve the greatest improvements?

New tools for improvement: The Affinity Diagram, Interrelationship Digraph, Tree Diagram, Prioritization Grid, Matrix Diagram, Process Decision Program Chart.

Affinity Diagram: Organizes a large number of ideas into their natural relationships. Used: After a brainstorming exercise, When analyzing verbal data, such as survey results. Then we organize ideas in categories. Ex. Proposed performance measures: Product Quality, Maintenance, Manufacturing Cost, Safety and Environmental, Volume

Interrelationship Digraph: Identify, analyze and classify the cause and effect relationships that exist among all critical issues so that key drivers or outcomes can become the heart of an effective solution. Is used to show cause-and-effect relationships between identified factors surrounding an issue.Is there a cause/influence relationship? If yes, which direction of cause/influence is stronger? Identify visually both the key drivers (the greatest number of outgoing arrows) and the key outcomes (the greatest number of incoming arrows). Typical methods are double boxes or bold boxes.

Tree Diagram: Identify the steps needed to address the given problem. It is used to break down broad categories into finer and finer levels of detail. Move step by step from generalities to specifics. Fundamental goals are broken down in strategic objectives. Lag indicators are long-term and results-oriented. Lead indicators are short-term and process-oriented.

Prioritization Grid: Is used to make decisions based on multiple criteria. It involves assigning percentages and weights to each criterion and ranking them.

Matrix Diagram: Identify correlations between variables. The vertical (up) arrow is a driving cause and the horizontal (side) arrow is an effect. We may have added symbols indicating the strength of the relationships. The "total" column is the sum of all of the "relationship strengths" in each row. This shows that you are working on those items that have the strongest effect on the greatest number of issues.

Process Decision Program Chart: Identifies what might go wrong in a plan under development. By using PDPC, a company either revises the plan to avoid the problems or can be ready with the best response when a problem occurs. // Obtain or develop a tree diagram of the proposed plan. This should be a high-level diagram showing the objective, a second level of main activities and a third level of broadly defined tasks to accomplish the main activities. For each task on the third level, brainstorm what could go wrong. Review all the potential problems and eliminate any that are improbable or whose consequences would be insignificant. Show the problems as a fourth level linked to the tasks. For each potential problem, brainstorm possible countermeasures. These might be actions or changes to the plan that would prevent the problem, or actions that would remedy it once it occurred. Show the countermeasures as a fifth level, outlined in clouds or jagged lines. Decide how practical each countermeasure is. Use criteria such as cost, time required, ease of implementation and effectiveness. Mark impractical countermeasures with an X and practical ones with an O.

Tools of Quality Management – Case Examples PDPC: Sample problem– Central Theme (Level 0)

The problem: What will make the next generation of organizations competitive? // The tool: Process Decision Program Chart // Level 0: Central theme

PDPC: Level 1 – Initiatives Establish measurement systems that improve processes and outcomes. Monitor the costs of non-quality. Scan the environment for new trends and needs.

PDPC: Level 2 – Topics Create customer focused measures to improve problem solving. Develop core process focused measures to improve downtimes. Develop behavioral measures to enhance cooperation

PDPC: Level 3 – Big Ideas Do real-time surveys to track customer priorities.

PDPC: Level 4 – Supporting Ideas Use industry survey databases. Create a database from website comments and questions. Use Pareto Charts, Affinity Diagram to analyse the information from the database.

The problem: How can we foster team creativity so that better solutions can be developed?

Create environment to support innovative team-centered problem solving

Train on appropriate skills to enable team members to work effectively

Pick the right team to get rich input of ideas

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