The seven basic quality tools, also known in the industry as 7QC Tools, are used within the context of the PDCA
Cycle to solve quality-related problems. As conceptually illustrated in Figure 8-7, the seven basic quality tools are:
• Cause-and-effect diagrams, which are also known as fishbone diagrams or as Ishikawa diagrams. The
problem statement placed at the head of the fishbone is used as a starting point to trace the problem’s
source back to its actionable root cause. The problem statement typically describes the problem as a gap
to be closed or as an objective to be achieved. The causes are found by looking at the problem statement
and asking “why” until the actionable root cause has been identified or until the reasonable possibilities
on each fishbone have been exhausted. Fishbone diagrams often prove useful in linking the undesirable
effects seen as special variation to the assignable cause upon which project teams should implement
corrective actions to eliminate the special variation detected in a control chart.
• Flowcharts, which are also referred to as process maps because they display the sequence of steps and
the branching possibilities that exist for a process that transforms one or more inputs into one or more
outputs. Flowcharts show the activities, decision points, branching loops, parallel paths, and the overall
order of processing by mapping the operational details of procedures that exist within a horizontal value
chain of a SIPOC model (Figure 8-6). Flowcharts may prove useful in understanding and estimating
the cost of quality in a process. This is obtained by using the workflow branching logic and associated
relative frequencies to estimate expected monetary value for the conformance and nonconformance
work required to deliver the expected conforming output.
Licensed To: Jorge Diego Fuentes Sanchez PMI MemberID: 2399412
This copy is a PMI Member benefit, not for distribution, sale, or reproduction.
237 ©2013 Project Management Institute.A Guide to the Project Management Body of Knowledge (PMBOK
®
Guide) – Fifth Edition
8 - PROJECT QUALITY MANAGEMENT
8
Requirements and
Feedback Loop
Requirements and
Feedback Loop
OUTPUT INPUT
PROCESS CUSTOMER SUPPLIER
Suppliers Inputs Process Outputs Customers
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Requirements List Measurements List Requirements List Measurements List
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
NOTE:The components of this diagram are flexible and can take any direction depending upon the circumstance.
Figure 8-6. the SIPocModel
• Checksheets, which are also known as tally sheets and may be used as a checklist when gathering data.
Checksheets are used to organize facts in a manner that will facilitate the effective collection of useful
data about a potential quality problem. They are especially useful for gathering attributes data while
performing inspections to identify defects. For example, data about the frequencies or consequences of
defects collected in checksheets are often displayed using Pareto diagrams.
• Pareto diagrams, exist as a special form of vertical bar chart and are used to identify the vital few sources
that are responsible for causing most of a problem’s effects. The categories shown on the horizontal
axis exist as a valid probability distribution that accounts for 100% of the possible observations. The
relative frequencies of each specified cause listed on the horizontal axis decrease in magnitude until the
default source named “other” accounts for any nonspecified causes. Typically, the Pareto diagram will be
organized into categories that measure either frequencies or consequences.
Licensed To: Jorge Diego Fuentes Sanchez PMI MemberID: 2399412
This copy is a PMI Member benefit, not for distribution, sale, or reproduction.
238 ©2013 Project Management Institute.A Guide to the Project Management Body of Knowledge (PMBOK
®
Guide) – Fifth Edition
8 - PROJECT QUALITY MANAGEMENT
• Histograms, are a special form of bar chart and are used to describe the central tendency, dispersion, and
shape of a statistical distribution. Unlike the control chart, the histogram does not consider the influence
of time on the variation that exists within a distribution.
• Control charts, are used to determine whether or not a process is stable or has predictable performance.
Upper and lower specification limits are based on requirements of the agreement. They reflect
the maximum and minimum values allowed. There may be penalties associated with exceeding the
specification limits. Upper and lower control limits are different from specification limits. The control
limits are determined using standard statistical calculations and principles to ultimately establish the
natural capability for a stable process. The project manager and appropriate stakeholders may use the
statistically calculated control limits to identify the points at which corrective action will be taken to
prevent unnatural performance. The corrective action typically seeks to maintain the natural stability of a
stable and capable process. For repetitive processes, the control limits are generally set at ±3 s around
a process mean that has been set at 0 s. A process is considered out of control when: (1) a data point
exceeds a control limit; (2) seven consecutive plot points are above the mean; or (3) seven consecutive
plot points are below the mean. Control charts can be used to monitor various types of output variables.
Although used most frequently to track repetitive activities required for producing manufactured lots,
control charts may also be used to monitor cost and schedule variances, volume, and frequency of scope
changes, or other management results to help determine if the project management processes are in
control.
• Scatter diagrams, plot ordered pairs (X, Y) and are sometimes called correlation charts because they seek
to explain a change in the dependent variable, Y, in relationship to a change observed in the corresponding
independent variable, X. The direction of correlation may be proportional (positive correlation), inverse
(negative correlation), or a pattern of correlation may not exist (zero correlation). If correlation can be
established, a regression line can be calculated and used to estimate how a change to the independent
variable will influence the value of the dependent variable.
Licensed To: Jorge Diego Fuentes Sanchez PMI MemberID: 2399412
This copy is a PMI Member benefit, not for distribution, sale, or reproduction.
239 ©2013 Project Management Institute.A Guide to the Project Management Body of Knowledge (PMBOK
®
Guide) – Fifth Edition
8 - PROJECT QUALITY MANAGEMENT
8
Cause & Effect Diagram Flowcharts Checksheets
Pareto Diagrams Histograms Control Charts
Scatter Diagrams
Figure 8-7. Storyboard Illustrating a conceptual Example of Each of the Seven Basic Quality tool
Cycle to solve quality-related problems. As conceptually illustrated in Figure 8-7, the seven basic quality tools are:
• Cause-and-effect diagrams, which are also known as fishbone diagrams or as Ishikawa diagrams. The
problem statement placed at the head of the fishbone is used as a starting point to trace the problem’s
source back to its actionable root cause. The problem statement typically describes the problem as a gap
to be closed or as an objective to be achieved. The causes are found by looking at the problem statement
and asking “why” until the actionable root cause has been identified or until the reasonable possibilities
on each fishbone have been exhausted. Fishbone diagrams often prove useful in linking the undesirable
effects seen as special variation to the assignable cause upon which project teams should implement
corrective actions to eliminate the special variation detected in a control chart.
• Flowcharts, which are also referred to as process maps because they display the sequence of steps and
the branching possibilities that exist for a process that transforms one or more inputs into one or more
outputs. Flowcharts show the activities, decision points, branching loops, parallel paths, and the overall
order of processing by mapping the operational details of procedures that exist within a horizontal value
chain of a SIPOC model (Figure 8-6). Flowcharts may prove useful in understanding and estimating
the cost of quality in a process. This is obtained by using the workflow branching logic and associated
relative frequencies to estimate expected monetary value for the conformance and nonconformance
work required to deliver the expected conforming output.
Licensed To: Jorge Diego Fuentes Sanchez PMI MemberID: 2399412
This copy is a PMI Member benefit, not for distribution, sale, or reproduction.
237 ©2013 Project Management Institute.A Guide to the Project Management Body of Knowledge (PMBOK
®
Guide) – Fifth Edition
8 - PROJECT QUALITY MANAGEMENT
8
Requirements and
Feedback Loop
Requirements and
Feedback Loop
OUTPUT INPUT
PROCESS CUSTOMER SUPPLIER
Suppliers Inputs Process Outputs Customers
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Requirements List Measurements List Requirements List Measurements List
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
NOTE:The components of this diagram are flexible and can take any direction depending upon the circumstance.
Figure 8-6. the SIPocModel
• Checksheets, which are also known as tally sheets and may be used as a checklist when gathering data.
Checksheets are used to organize facts in a manner that will facilitate the effective collection of useful
data about a potential quality problem. They are especially useful for gathering attributes data while
performing inspections to identify defects. For example, data about the frequencies or consequences of
defects collected in checksheets are often displayed using Pareto diagrams.
• Pareto diagrams, exist as a special form of vertical bar chart and are used to identify the vital few sources
that are responsible for causing most of a problem’s effects. The categories shown on the horizontal
axis exist as a valid probability distribution that accounts for 100% of the possible observations. The
relative frequencies of each specified cause listed on the horizontal axis decrease in magnitude until the
default source named “other” accounts for any nonspecified causes. Typically, the Pareto diagram will be
organized into categories that measure either frequencies or consequences.
Licensed To: Jorge Diego Fuentes Sanchez PMI MemberID: 2399412
This copy is a PMI Member benefit, not for distribution, sale, or reproduction.
238 ©2013 Project Management Institute.A Guide to the Project Management Body of Knowledge (PMBOK
®
Guide) – Fifth Edition
8 - PROJECT QUALITY MANAGEMENT
• Histograms, are a special form of bar chart and are used to describe the central tendency, dispersion, and
shape of a statistical distribution. Unlike the control chart, the histogram does not consider the influence
of time on the variation that exists within a distribution.
• Control charts, are used to determine whether or not a process is stable or has predictable performance.
Upper and lower specification limits are based on requirements of the agreement. They reflect
the maximum and minimum values allowed. There may be penalties associated with exceeding the
specification limits. Upper and lower control limits are different from specification limits. The control
limits are determined using standard statistical calculations and principles to ultimately establish the
natural capability for a stable process. The project manager and appropriate stakeholders may use the
statistically calculated control limits to identify the points at which corrective action will be taken to
prevent unnatural performance. The corrective action typically seeks to maintain the natural stability of a
stable and capable process. For repetitive processes, the control limits are generally set at ±3 s around
a process mean that has been set at 0 s. A process is considered out of control when: (1) a data point
exceeds a control limit; (2) seven consecutive plot points are above the mean; or (3) seven consecutive
plot points are below the mean. Control charts can be used to monitor various types of output variables.
Although used most frequently to track repetitive activities required for producing manufactured lots,
control charts may also be used to monitor cost and schedule variances, volume, and frequency of scope
changes, or other management results to help determine if the project management processes are in
control.
• Scatter diagrams, plot ordered pairs (X, Y) and are sometimes called correlation charts because they seek
to explain a change in the dependent variable, Y, in relationship to a change observed in the corresponding
independent variable, X. The direction of correlation may be proportional (positive correlation), inverse
(negative correlation), or a pattern of correlation may not exist (zero correlation). If correlation can be
established, a regression line can be calculated and used to estimate how a change to the independent
variable will influence the value of the dependent variable.
Licensed To: Jorge Diego Fuentes Sanchez PMI MemberID: 2399412
This copy is a PMI Member benefit, not for distribution, sale, or reproduction.
239 ©2013 Project Management Institute.A Guide to the Project Management Body of Knowledge (PMBOK
®
Guide) – Fifth Edition
8 - PROJECT QUALITY MANAGEMENT
8
Cause & Effect Diagram Flowcharts Checksheets
Pareto Diagrams Histograms Control Charts
Scatter Diagrams
Figure 8-7. Storyboard Illustrating a conceptual Example of Each of the Seven Basic Quality tool
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