Quality Planning: Tools and Techniques

• Prevention keeping errors out of the process and inspection keeping errors out of the hands of the customer. • Attribute sampling the result conforms, or it does not and variables sampling the result is rated on a continuous scale that measures the degree of conformity. • Special causes unusual events and common causes normal process variation. Common causes are also called random causes. • Tolerances the result is acceptable if it falls within the range specified by the tolerance and control limits the process is in control if the result falls within the control limits. 8 Figure 8-5. Perform Quality Control: Inputs, Tools Techniques, and Outputs

8.3.1 Perform Quality Control: Inputs

.1 Quality Management Plan Described in Section 8.1.3.1. .2 Quality Metrics Described in Section 8.1.3.2. .3 Quality Checklists Described in Section 8.1.3.3. .4 Organizational Process Assets Described in Section 4.1.1.4. .5 Work Performance Information Work performance information Section 4.4.3.7, including technical performance measures, project deliverables completion status, and the implementation of required corrective actions, are important inputs to QC. Information from the project management plan about the planned or expected results should be available along with information about the actual results and implemented change requests. A Guide to the Project Management Body of Knowledge PMBOK ® Guide Third Edition 2004 Project Management Institute, Four Campus Boulevard, Newtown Square, PA 19073-3299 USA 191 .6 Approved Change Requests Approved change requests Section 4.4.1.4 can include modifications such as revised work methods and revised schedule. The timely correct implementation of approved changes needs to be verified. .7 Deliverables Described in Section 4.4.3.1.

8.3.2 Perform Quality Control: Tools and Techniques

The first seven of these are known as the Seven Basic Tools of Quality. .1 Cause and Effect Diagram Cause and effect diagrams, also called Ishikawa diagrams or fishbone diagrams, illustrate how various factors might be linked to potential problems or effects. Figure 8-6 is an example of a cause and effect diagram. Figure 8-6. Cause and Effect Diagram .2 Control Charts A control charts purpose is to determine whether or not a process is stable or has predictable performance. Control charts may serve as a data gathering tool to show when a process is subject to special cause variation, which creates an out-of-control condition. Control charts also illustrate how a process behaves over time. They are a graphic display of the interaction of process variables on a process to answer the question: Are the process variables within acceptable limits? Examination of the non-random pattern of data points on a control chart may reveal wildly fluctuating values, sudden process jumps or shifts, or a gradual trend in increased variation. By monitoring the output of a process over time, a control chart can be employed to assess whether the application of process changes resulted in the desired improvements. When a process is within acceptable limits, the process need not be adjusted. When a process is outside acceptable limits, the process should be adjusted. The upper control limit and lower control limit are usually set at +- 3 sigma i.e., standard deviation. A Guide to the Project Management Body of Knowledge PMBOK ® Guide Third Edition 192 2004 Project Management Institute, Four Campus Boulevard, Newtown Square, PA 19073-3299 USA