quality control tools. introduction by: mark rigor mirondo the perform quality control process of...

Quality Control

Tools

IntroductionIntroduction

By: Mark Rigor MirondoBy: Mark Rigor MirondoBy: Mark Rigor MirondoBy: Mark Rigor Mirondo

The Perform Quality Control process of the Project The Perform Quality Control process of the Project Quality Management knowledge area has several quality Quality Management knowledge area has several quality control tools and techniques that are also used in the control tools and techniques that are also used in the Perform Quality Assurance process. The quality control Perform Quality Assurance process. The quality control tools and techniques discussed in this article are:tools and techniques discussed in this article are: Cause and Effect

Diagrams Check Sheet Control Charts Histogram Pareto Chart Scatter Diagram Stratification

Cause and Effect DiagramCause and Effect Diagram

Fishbone DiagramFishbone DiagramAlso Called: Cause-and-Effect Diagram, Ishikawa Also Called: Cause-and-Effect Diagram, Ishikawa

DiagramDiagramVariations: cause enumeration diagram, process fishbone, Variations: cause enumeration diagram, process fishbone, time-delay fishbone, CEDAC (cause-and-effect diagram time-delay fishbone, CEDAC (cause-and-effect diagram with the addition of cards), desired-result fishbone, reverse with the addition of cards), desired-result fishbone, reverse fishbone diagramfishbone diagram DescriptionDescription

The fishbone diagram identifies many possible The fishbone diagram identifies many possible causes for an effect or problem. It can be used to structure causes for an effect or problem. It can be used to structure a brainstorming session. It immediately sorts ideas into a brainstorming session. It immediately sorts ideas into useful categories.useful categories.

When to Use a Fishbone DiagramWhen to Use a Fishbone DiagramWhen identifying possible causes for a problem.When identifying possible causes for a problem.Especially when a team’s thinking tends to fall into ruts.Especially when a team’s thinking tends to fall into ruts.By: Mark Rigor MirondoBy: Mark Rigor MirondoBy: Mark Rigor MirondoBy: Mark Rigor Mirondo

Check SheetCheck Sheet

Check SheetCheck SheetAlso called: defect concentration diagramAlso called: defect concentration diagram

DescriptionDescriptionA check sheet is a structured, prepared form for A check sheet is a structured, prepared form for

collecting and analyzing data. This is a generic tool that collecting and analyzing data. This is a generic tool that can be adapted for a wide variety of purposes.can be adapted for a wide variety of purposes.

When to Use a Check SheetWhen to Use a Check SheetWhen data can be observed and collected repeatedly by When data can be observed and collected repeatedly by the same person or at the same location.the same person or at the same location.When collecting data on the frequency or patterns of When collecting data on the frequency or patterns of events, problems, defects, defect location, defect causes, events, problems, defects, defect location, defect causes, etc.etc.When collecting data from a production process.When collecting data from a production process.


Control ChartsControl Charts

Control ChartControl ChartAlso called: statistical process controlAlso called: statistical process control

DescriptionDescriptionThe control chart is a graph used to study The control chart is a graph used to study

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


When to Use a Control ChartWhen to Use a Control ChartWhen controlling ongoing processes by finding and When controlling ongoing processes by finding and correcting problems as they occur.correcting problems as they occur.When predicting the expected range of outcomes from a When predicting the expected range of outcomes from a process.process.When determining whether a process is stable (in When determining whether a process is stable (in statistical control).statistical control).When analyzing patterns of process variation from When analyzing patterns of process variation from special causes (non-routine events) or common causes special causes (non-routine events) or common causes (built into the process).(built into the process).When determining whether your quality improvement When determining whether your quality improvement project should aim to prevent specific problems or to make project should aim to prevent specific problems or to make fundamental changes to the process.fundamental changes to the process.

Control ChartsControl Charts


HistogramHistogram

Source: Nayatani, Y., The Seven New QC Tools (Tokyo, Japan, 3A Corporation, 1984)

DescriptionDescriptionA frequency distribution shows how often each A frequency distribution shows how often each

different value in a set of data occurs. A histogram is the different value in a set of data occurs. A histogram is the most commonly used graph to show frequency most commonly used graph to show frequency distributions. It looks very much like a bar chart, but distributions. It looks very much like a bar chart, but there are important differences between them.there are important differences between them.

When to Use a HistogramWhen to Use a HistogramWhen the data are numerical.When the data are numerical.When you want to see the shape of the data’s When you want to see the shape of the data’s distribution, distribution, especially when determining whether the especially when determining whether the output of a output of a process is distributed approximately process is distributed approximately normally.normally.


Pareto ChartPareto Chart

Pareto ChartPareto ChartAlso called: Pareto diagram, Pareto analysisAlso called: Pareto diagram, Pareto analysis

Variations: weighted Pareto chart, comparative Pareto Variations: weighted Pareto chart, comparative Pareto chartscharts

DescriptionDescriptionA Pareto chart is a bar graph. The lengths of the A Pareto chart is a bar graph. The lengths of the

bars represent frequency or cost (time or money), and are bars represent frequency or cost (time or money), and are arranged with longest bars on the left and the shortest to arranged with longest bars on the left and the shortest to the right. In this way the chart visually depicts which the right. In this way the chart visually depicts which situations are more significant.situations are more significant.

When to Use a Pareto ChartWhen to Use a Pareto ChartWhen analyzing data about the frequency of problems or When analyzing data about the frequency of problems or causes causes in a process.in a process.When there are many problems or causes and you want When there are many problems or causes and you want to focus to focus on the most significant.on the most significant.


Scatter DiagramScatter Diagram

Scatter DiagramScatter DiagramAlso called: scatter plot, X–Y graphAlso called: scatter plot, X–Y graph

DescriptionDescriptionThe scatter diagram graphs pairs of numerical data, The scatter diagram graphs pairs of numerical data,

with one variable on each axis, to look for a relationship with one variable on each axis, to look for a relationship between them. If the variables are correlated, the points between them. If the variables are correlated, the points will fall along a line or curve. The better the correlatin, the will fall along a line or curve. The better the correlatin, the tighter the points will hug the line.tighter the points will hug the line.

When to Use a Scatter DiagramWhen to Use a Scatter DiagramWhen you have paired numerical data.When you have paired numerical data.When your dependent variable may have multiple values When your dependent variable may have multiple values for each for each value of your independent variable.value of your independent variable.


StratificationStratification

DescriptionDescription

Stratification is a technique used in combination Stratification is a technique used in combination with other data analysis tools. When data from a variety of with other data analysis tools. When data from a variety of sources or categories have been lumped together, the sources or categories have been lumped together, the meaning of the data can be impossible to see. This meaning of the data can be impossible to see. This technique separates the data so that patterns can be seen.technique separates the data so that patterns can be seen.

When to Use StratificationWhen to Use StratificationBefore collecting data.Before collecting data.

When data come from several sources or conditions, such When data come from several sources or conditions, such as shifts, days of the week, suppliers or population groups.as shifts, days of the week, suppliers or population groups.When data analysis may require separating different When data analysis may require separating different sources or conditions.sources or conditions.


Thank You!!!Thank You!!!

Members:Members:

Mark Rigor MirondoMark Rigor MirondoMhelan DasallaMhelan Dasalla

Almarie FernandoAlmarie FernandoRoderick GalletoRoderick Galleto


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