Cause & Effect Diagram

The cause & effect diagram is the brainchild of Kaoru Ishikawa, who pioneered quality management processes in the Kawasaki shipyards, and in the process became one of the founding fathers of modern management. The cause and effect diagram is used to explore all the potential or real causes (or inputs) that result in a single effect (or output). Causes are arranged according to their level of importance or detail, resulting in a depiction of relationships and hierarchy of events. This can help you search for root causes, identify areas where there may be problems, and compare the relative importance of different causes.
Causes in a cause & effect diagram are frequently arranged into four major categories. While these categories can be anything, you will often see:

• manpower, methods, materials, and machinery (recommended for manufacturing)
• equipment, policies, procedures, and people (recommended for administration and service).

These guidelines can be helpful but should not be used if they limit the diagram or are inappropriate. The categories you use should suit your needs. At SkyMark, we often create the branches of the cause and effect tree from the titles of the affinity sets in a preceding affinity diagram.
The C&E diagram is also known as the fishbone diagram because it was drawn to resemble the skeleton of a fish, with the main causal categories drawn as "bones" attached to the spine of the fish, as shown below.

How to use it:

Before constructing the Cause-and-Effect Diagram, you need to analyze the causes. The steps are as follows:

1. Re-examine the problem by asking:
   • What is the problem?
   • Who is affected?
   • When does it occur?
   • Where does it occur?
     
2. Brainstorm the team's ideas about the causes of a problem using the Causal Table or "Why-Because" Technique.
   
3. The list of causes should be grouped by relationships or common factors using an affinity technique.
4. You can now illustrate graphically the causes grouped by relationships by using a Cause-and-Effect Diagram where:
   
   
   • The problem under investigation is described in a box at the head of the diagram.
   • A long spine with an arrow pointing towards the head forms the backbone of the "fish." The direction of the arrow indicates that the items that feed into the spine might cause the problem described in the head.
     
   • A few large bones feed into the spine. These large bones represent the main categories of potential causes of the problem. Again, the arrows represent the direction of the action; the items on the larger bones are thought to cause the problem in the head.
     
   • The smaller bones represent deeper causes of the larger bones they are attached to. Each bone is a link in a Cause-and-Effect chain that leads from the deepest causes to the targeted problem. 
   
   
   
   
   • 

1.Cause and effect tool that helps identify , sort and display possible causes of a problem or quality characterstics.

2. Please note that it is NOT used to identify the root cause. Only data can do that.

Benefits of using cause and effect diagram

1.Helps determine possible cause
2.Encourages group participation
3.Uses an orderly , easy to read format
4.Indicate possible cause of variation
5.Increase process knowledge
6.Identify areas for collecting data

Quality Management 8.3 Perform Quality Control

Quick Link for Quality Management

Quality Management 8.1 Plan quality

Quality Management 8.2 perform quality assurance

Quality Management 8.3 Perform Quality Control

Quality control involves monitoring and recording specific project results to assess performance and recommend necessary changes. Project results include both product deliverables and project performance measures such as cost and schedule.

Project teams should know the differences between:

·         Prevention (keeping errors out of the process) and inspection (keeping errors away from the customer).

·         Attribute sampling (the result conforms or it does not) and variables sampling (results are measured to determine the degree of conformity).

·         Tolerances (the result is acceptable if it's within the range specified by the tolerance) and control limits (the process is in control if the result falls within the control limits).

Perform quality control
Inputs	Tools	Outputs
1.       Project management Plan 2.       Quality metrics 3.       Quality checklists 4.       Work performance measurements 5.       Approved change requests 6.       Deliverables 7.       Organizational process assets	1.       Cause and effect diagrams 2.       Control charts 3.       Flowcharting 4.       Histogram 5.       Pareto chart 6.       Run chart 7.       Scatter diagram 8.       Statistical sampling 9.       Inspection 10.   Approved change requests review	1.       Quality control measurements 2.       Validated changes 3.       Validated deliverables 4.       OPA updates 5.       Change requests 6.       Project management Plan updates 7.       Project document updates

Seven Key lnputs for Perform Quality Control:

1.       Project Management Plan: Contains the quality management plan which documents how quality control is to be handled.

2.       Quality Metrics: Also known as operational definitions, metrics describe how something will be measured. Quality metrics might include failure rates and reliability. A related project performance metric might measure whether an activity is on time (A decision would have to be made as to whether on time means starting on time, finishing on time, or both).

3.       Quality Checklists: A structured tool to verify that all steps in a process have been performed. Checklists are often used in the quality management process, especially in a complex or for tasks performed frequently.

4.       Work Performance Measurements: Contains measures of actual progress which are compared to planned progress. These metrics include:

·         Planned vs. actual technical performance

·         Planned vs. actual schedule performance

·         Planned vs. actual cost performance

5.       Approved Change Requests: Approved changes may affect work methods, schedules, and defect repairs. The correct and timely implementation of approved changes must be verified.

6.       Deliverables: Described in Section 4.3.3.1 (any verifiable product or result).

7.       Organizational Process Assets: Organizational Process Assets that may affect quality control include:

·         Quality standards and policies

·         Standard work guidelines

·         Procedures and policies for issue reporting, defect reporting, and communication

1.    Ten Key Tools for Perform Quality Control:

1.       Cause and Effect Diagram: You must know that cause and effect diagrams are also called lshikawa or Fishbone diagrams. They are used to illustrate the possible factors that may be causing or influencing certain problems. PMI also emphasizes that they may be used to stimulate thinking and discussion.

2.       Control charts: Control charts are used to determine whether a process is stable (under control) and is therefore producing predictable results. The charts track three major types of data:

a.       Specification limits are requirements in the contract,

b.      Control limits define points at which corrective action is considered and 

c.       There is a planned goal (the perfect outcome). 

Control charts are graphic, time-based displays of process results. The charts are used to determine whether a process is under control. In other words, are the differences in the results caused by random variations or are they the result of "special causes" that indicate a need for corrective action? The following list reviews key points:

·         Control limits indicate how much variation is inherent in a process. control limits are often at a range of plus or minus three sigma (where sigma is the standard deviation of process outcomes).

·         Outcomes outside the control limits are referred as special causes (or assignable causes) and indicate a need for corrective action.

·         Specification limits are established in the contract and represent customer demands (how much variation is allowable before the results are rejected or penalized in some way). This concept is also referred to as a tolerance.

3.       Flow charting: Described in Section 8.1.2.7. Flowcharts are diagrams used to help analyze how problems occur. Most flowcharts show activities, decision points, and the sequence in which process steps occur. These diagrams help improve processes and help anticipate where problems might occur.

4.       Histogram: A vertical bar chart that rank orders or prioritizes data. The next tool, Pareto chart, is an example of a histogram.

5.       Pareto chart: A histogram (vertical bar chart) ordered by the frequency of occurrence that shows results by specific causes. The greatest cause of defects or variances is shown as the tallest bar on the left of the chart. The causes are rank ordered from left to right, and the rank ordering is used to guide corrective action-the greatest cause of variance is worked on first.

The tool was named after an Italian economist who discovered that 80% of the wealth in a particular region in Europe was held by only 2a% of the population. This discovery eventually was dubbed the 80/20 rule, indicating the importance of focusing efforts toward improvement on the "significant few."

6.       Run chart: Trend analysis is performed using a run chart, which is a line graph that plots data points in the order in which they occur (i.e., on a time scale). The data may show:

·         Variation

·         Declines or improvements over time

·         Trends

7.       Scatter Diagram: Shows the relationship between two variables known as the dependent and the independent variables. 

8.       Statistical Sampling: Choosing part of a population for inspection. For example, one might examine 150 of the 1,000 welds on a bridge construction project to determine whether the welds conform to requirements. Sampling is done to reduce the cost of quality control.

For the exam, you should know the conditions under which sampling is most appropriate:

·         When the population is large

·         When the cost of inspection is high

·         When destructive testing is required (duh)

·         When you believe there are not many defects

Attribute sampling looks for the presence or absence of particular defects. Variable sampling provides the basis for control charts by numerically measuring the degree of conformity for particular factors.

9.       Inspection: The examination of a work product to determine whether it conforms to standards. Inspections generally include measurements and may be conducted at any level (the final product, a sub-system, or a single activity). As before, other names include reviews, audits, and walkthroughs.

10.   Approved Change Requests Review: These reviews are designed to ensure that approved change requests were implemented correctly.

Seven Key Outputs for Perform Quality Control:

1.       Quality Control Measurements: As described in quality assurance, these measurements are used as feedback to QA to reevaluate any quality standards currently in use.

2.       Validated Changes: Repaired or changed items are inspected and either accepted or rejected. Rejected items may require rework.

3.       Validated Deliverable: A major goal of quality control is to ensure that deliverables are correct. Validated deliverable are inputs to Verify Scope (Section 5.4) for formal acceptance.

4.       Organizational Process Assets Updates: Recording the use of checklists and incorporating those records into the historical database of the organization.

5.       Change requests: If recommended corrective actions, preventive actions or defect repairs lead to change requests, the requests must be processed using integrated change control.

6.       Project management plan updates: Portions of the project management plan that may be updated include:

·         Quality management plan

·         Process improvement plan

7.       Project document updates: Documents that may be updated include quality standards.

Quality Management 8.2 perform quality assurance

Quick Link for Quality Management

Quality Management 8.1 Plan quality

Quality Management 8.2 perform quality assurance

Quality Management 8.3 Perform Quality Control

Quality assurance involves auditing requirements and results from quality control measurements to ensure the project will use appropriate quality standards and processes.

Quality assurance is also the umbrella for continuous process improvement. Continuous improvement is aimed at identifying and reviewing all organizational processes so that increased efficiency and effectiveness can be achieved.

Quality assurance creates a management system for auditing quality requirements, reviewing organization process (audits) and capturing the results from quality control in the form of QC measurements. The QC feedback is used to determine whether adjustments are needed in the assurance system.

Perform Quality Assurance
Inputs	Tools	Outputs
1.       Project management plan 2.       Quality metrics 3.       work performance information 4.       Quality control measurements	1.       Plan quality and perform quality control tools and techniques 2.       Quality audits 3.       Process analysis	1.       OPA updates 2.       Change requests 3.       Project management plan updates 4.       Project document updates

Four key inputs for perform quality assurance:

1.       Project management plan: Contains the following information used in quality assurance:

·         Quality management plan (describes how quality assurance will be performed)

·         Process improvement plan (define how processes will be analyzed to improve outcomes)

2.       Quality metrics: Also known as operational definitions, metrics describe how something will be measured. Quality metrics might include failure rates and reliability. A related project performance metric might measure whether an activity is on time (A decision would have to be made as to whether on time means starting on time, finishing on time, or both).

3.       Work performance information: Actual performance outcomes collected at reporting intervals as the project progresses and include:

·         Technical performance measure

·         Status of project deliverables

·         Schedule progress

·         Costs incurred

4.       Quality control measurements: the results of quality control that are in turn fed back to Quality assurance to consider any potential changes in the organization’s quality standards and processes.

Three key tools for perform quality assurance:

1.       Plan quality and perform quality control tools and techniques: The tools for quality planning (section 8.1.2) and quality control (section 8.1.3) may also be used for quality assurance.

2.       Quality audits: structured, independent reviews to identify inefficient processes, reduce the cost of quality and increase the percentage of accepted products (preventing defects from occurring). The specific objectives of a quality audit may include:

·         Identify and share best practices

·         Identify shortcomings

·         Share the good practices from similar projects (lessons learned)

·         Proactively offer assistance to improve progresses and raise productively

·         Document the lessons learned from each audit

Audits may be scheduled or random and they be conducted by internal or external auditors.

3.       Project analysis: Identifies and implements needed improvements by using the process improvement plans mentioned earlier (8.1.3.4).

Four key outputs for perform quality assurance:

1.       Organizational process assets updates: Any updates to established quality standards.

2.       Change requests: Quality improvement includes any action to improve effectiveness. Change requests may be take corrective action, preventive action or perform defect repair. As always, change requests are processed using integrated change control (section 4.5).

3.       Project management plan updates: Portions of the project management plan that may be updated as a result of quality assurance include:

·         Quality management plan

·         Schedule management plan

·         Cost management plan

4.       Project document updates: May include the following:

·         Quality audit reports

·         Training plans

·         Process documentation

Additional information about quality assurance:

The quality assurance system should provide three things:

·         Auditing

·         Feedback

·         Correction

Quality evaluation: There are two kinds of evolution you should know about for exam. They are:

·         Formative (also called a quality audit): Done during the project for the purpose of making corrections.

·         Summative (also called quality improvement): done after the project for the purpose of documenting lessons learned.

Quality responsibility: responsibility for quality can be viewed two ways (be careful of the exact wording on this topic):

1.          Responsibility for a task: Belongs to the individual employee performing the task.

2.          Responsibility for the project: Belongs to the project manager.