The Basic Seven (B7) Tools of Quality

What are the Basic Seven Tools of Quality?Fishbone DiagramsHistogramsPareto AnalysisFlowchartsScatter PlotsCheck sheetsControl Charts

Where did the Basic Seven come from?Kaoru IshikawaKnown for Democratizing Statistics(Democratizing Statistics refers to the will of Ishikawa to spread Quality control throughout the workplace. The desire to make Quality control comprehendible for all of the workers.)

The Basic Seven Tools made statistical analysis less complicated for the average person

Good Visual Aids make statistical and quality control more comprehendible.

The Basic Seven (B7) Tools of QualityFishbone Diagrams (Also known as Ishikawa Diagrams and Cause and Effect Diagrams. )

No statistics involved

Maps out a process/problem

Makes improvement easier

Looks like a Fish Skeleton

Constructing a Fishbone DiagramStep 1 - Identify the Problem (head)Step 2 - Draw spine and bones

Example: High Inventory Shrinkage at local Drug Store

Shrinkage

Constructing a Fishbone DiagramStep 3 - Identify different areas where problems may arise fromEx. : High Inventory Shrinkage at local Drug Store

Shrinkageemployeesshoplifters

Constructing a Fishbone DiagramStep 4 - Identify what these specific causes could be

Ex. : High Inventory Shrinkage at local Drug Store

ShrinkageshopliftersAnti-theft tags poorly designedExpensive merchandise out in the openNo security/ surveillance

Constructing a Fishbone DiagramEx. : High Inventory Shrinkage at local Drug Store

ShrinkageshopliftersAnti-theft tags poorly designedExpensive merchandise out in the openNo security/ surveillance

employeesattitudenew traineetrainingbenefitspractices

Constructing a Fishbone DiagramStep 5 Use the finished diagram to brainstorm solutions to the main problems.

Moving expensive merchandise behind the counters and educating employees to their perks may be some solutions to this problem.

The Basic Seven (B7) Tools of QualityHistograms

Bar chart

Used to graphically represent groups of data

Constructing a HistogramUse range to estimate beginning and end Calculate the width of each column by dividing the range by the number of columnsRange# of Columns= Width

Acme Pizza ExampleLets say the owner wants a distribution of Acmes Thursday Night SalesData Set from last Thursday(slices)2 1 2 2 4 1 3 1 2 1 2 2 4 3 4 1 4 3 2 2 3 2 1 2 2 1 2 2 1 4 2 2 1 2 1 2 2 1 2 1 2 1 2 1 2 1 2 1 2 2 2 1 2 1 2 1 1 2 2 2 3 1 4 2 2 3 2 2 2 1 2 3 2 2 4 2 2 4 4 1 2 2 2 3 2 2 1 2 2 4 2 1 2 4 2 1 7 2 1 2 2 3 1 2 1 1 2 1 2 2 2 1 0 2 2 1 2 1 2 2 2 4 2 4These numbers represent the customers order at the order window at the pizza store. For example, the first customer didnt order any pizza, the second ordered 2 slices, the third ordered 1 and so on. It should be noticed that the highest order was 7 slices and the lowest was 0.

Acme Pizza ExampleSlices of Pizza# times orderedHistogram

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Constructing a HistogramHow is this helpful to Acme?2 slices of pizza most common order placedDistribution of sales useful for forecasting next Thursdays night demand

If you were an Acme manager how could you apply this information?Most common types of orders placed is valuable information. Knowing that the average customer will order 2 slices of pizza can be implemented into Acmes strategic plan. By taking at least 2 slices up to the window at peak hours, this can improve Acmes customer service and speed. It makes the line move much faster making the perceived quality higher for the customer.

The Basic Seven (B7) Tools of QualityPareto AnalysisVery similar to HistogramsUse of the 80/20 ruleUse of percentages to show importanceVilfredo Pareto (1848-1923) originated the 80/20 Rule, which states that 80% of the problems comes from only 20% of the causes. Pareto Analysis is very similar to Histograms but it incorporates this theory into it. Pareto Analysis adds weight to the most frequently occurring things.

Acme PizzaThe % column represents the slices percentage of total frequency. This dictates the order of the Pareto diagram which is always scaled according to size.

No. of slicesNo. of Orders% Orders26554.17%13327.50%41210.00%386.67%010.83%710.83%500.00%600.00%1201

Acme Pizza

Acme PizzaCritical ThinkingHow does the Pareto Analysis differ from the Histogram?The Pareto Analysis Shows percentages. How can this be a useful tool to the Acme boss?Helps identify trends. Useful for quality improvements and planning processes.

The Basic Seven (B7) Tools of QualityFlowcharts

A graphical picture of a PROCESS

ProcessDecisionThe process flow

FlowchartsDont Forget to:

Define symbols before beginning

Stay consistent

Check that process is accurate

symbolsThe rectangle, diamond and line are the standard symbols for flowcharts. There can be extra/different symbols depending on the process/business. The important thing is that it is consistent and maps out the process efficiently. Once flowcharts are effectively drawn they can shed light on possible problems or improvements.

Want some practice?Make a flowchart for:

Cooking dinnerDriving a carHaving a party

Any other processes you can think of?

The Basic Seven (B7) Tools of QualityScatter Plots2 Dimensional X/Y plotsUsed to show relationship between independent(x) and dependent(y) variablesScatter plots take place on an X and Y graph. Whichever variable is on the bottom should be the dependent variable. This means that the Y variable changes according to changes in X. In the upcoming example, Minutes cooking the pizzas will directly affect the number of defective pies that are produced. Scatter plots are useful for finding direct or indirect relationships which can then be used to analyze/improve quality.

Acme Pizza (Scatter Diagram)Minutes Cooking Defective Pies10145830575 2060 14204256In this simple example, you can find the existing relationship without much difficulty butThis is meant to show the data. It isnt too difficult for students to see that there is a direct relationship between Minutes cooking and defects. But the Scatter Plot will make this easier to see.

Scatter DiagramsEasier to see direct relationshipThere is a direct relationship between time spent cooking by employees and defects. As Time cooking increases, so does the amount of defects.

Time Cooking (minutes)Defective Pizzas

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Scatter DiagramsAs a quality toolWhat does this tell Acme management about their processes?Improvements?There is obviously some kind of process problem with the number of defective pies being produced. Maybe the cooks are getting sloppy from working too fast. Or maybe morale is low and there is just apathetic work being done. Whatever the case, if this was actually happening, quality improvements would have to be studied and implemented.Time Cooking (minutes)Defective Pizzas

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Check sheetsPurpose:Tool for collecting and organizing measured or counted dataData collected can be used as input data for other quality tools

Benefits:Collect data in a systematic and organized mannerTo determine source of problemTo facilitate classification of data (stratification)

Check sheetsIn the top chart we see two operators and two machines. In the morning both operators and both machines seem to be working well. However in the afternoon we see both operators are more prone to defects and the machine two is very prone to problems. We conclude there may be some operator fatigue involved AND that there is some condition on machine two that needs to be investigated. Look for something that affects on machine but not the other like sun glareConditions, Workers, Material

The Basic Seven (B7) Tools of QualityControl ChartsDeviation from Mean

Upper and Lower Specs

Range Already Covered

Control ChartsUpper Limit

Lower LimitUnacceptable deviationX

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