Ch04 Metrics

8/7/2019 Ch04 Metrics

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Quality Metrics

Agenda Agenda Agenda Agenda

Review homework Chapter 3 - 11, 36(c)

Case Study: ³How We

Slashed Response Time´

Lecture/discussion

Chapter 4: Statistics

Metrics

Measurement Statistics

Week 8 assignment

Homew or k

P robl ems chapter 4

± 2, 3

Week 7



Quality Metrics

Quality MetricsQuality MetricsChapter Four

³We best manage what we canmeasure´



Quality Metrics

MetricMetric

A metric is a verifiable measure stated in

either quantitative or qualitative terms.

³95 percent inventory accuracy´ ³as evaluated by our customers, we are

providing above-average service´



Quality Metrics

MetricMetric

A metric is a verifiable measure

that

captures performance in terms of howsomething is being done relative to a

standard,

allows and encourages comparison,

supports business strategy.



Quality Metrics

Customer quality measuresCustomer quality measures

Customers typically relate quality to:

Feature based measures; ³have´ or ³havenot´ - determined by design

Performance measures - ³range of values´ -conformance to design or ideal value



Quality Metrics

Tr ue versus substituteTr ue versus substitute

performance measu

resperformance measu

res Customers - use ³true´ performance measures. example: a true measure of a car door may be ³easy to close´.

true performance measures typically vary by each individualcustomer.

Unfortunately, producers cannot measure performance as eachindividual customer does.

Producers - use ³substitute´ performance measures these measures are quantifiable (measurable units).

Substitute measure for a car door: door closing effort (foot-pounds).

Other example: light bulb true performance measure -- brightens the room

substitute performance measure ± wattage or lumens



Quality Metrics

Educating ConsumersEducating Consumers

Sometimes, producers educate consumers on

their substitute performance measures.

What are substitute performance measures for

the following customer desires:

Good Gas Mileage

Powerful Computer

What is the effect of educating consumers onperformance measures?



Quality Metrics

What is a ³metric´?What is a ³metric´?

Another term for a substitute performance

measure is a metric .

Metric is a standard of measurement.

In quality management, we use metrics to translate

customer needs into producer performance

measures.

Internal quality metrics scrap and rework

process capability (Cp or Cpk)

first time through quality (FTTQ)



Quality Metrics

Identifying effective metricsIdentifying effective metrics

Effective metrics satisfy the followingconditions: performance is clearly defined in a measurable

entity (quantifiable).

a capable system exists to measure the entity(e.g., a gage).

Effective metrics allow for actionableresponses if the performance is unacceptable. There is little value in a metric which identifies

nonperformance if nothing can or will be done toremedy it.

Example: Is net sales a good metric to measure theperformance of a manufacturing department?



Quality Metrics

Use of quality metricsUse of quality metrics

Quality metric data may be used to: spot trends in performance.

compare alternatives.

predict performance.

However, organizations should consider thecosts and benefits of collecting information for a particular quality metric. collecting data will not necessarily result in higher

performance levels.

higher quality companies often use fewer metricsthan their competitors.



Quality Metrics

Acceptable ranges Acceptable ranges

In practice, identifying effective metrics is oftendifficult.

Main reason: non-performance of a metric does not always leadto customer dissatisfaction.

Consider the car door example again, if door closingeffort is the metric, will a customer be dissatisfied if the actual effort is 50 foot-pounds versus 55 foot-pounds.

Producers typically identify ranges of acceptableperformance for a metric. (a) For services, ranges often referred to as break points.

(b) In manufacturing, these ranges are known as targets,tolerances, or specifications.



Quality Metrics

Break pointsBreak points

Break points are levels where improved performancewill likely change customer behavior.

Example: waiting in line

Suppose the average customer will only wait for 5 minutes Wait longer than 5 minutes -- customer is

dissatisfied.

1-5 minutes -- customer is satisfied.

less than 1 minute -- customer is extremely satisfied

Should a company try to reduce average wait timefrom 4 to 2 minutes.?



Quality Metrics

Targets, tolerances andTargets, tolerances and

specificationsspecifications Target (nominal) - desired value of a

characteristic.

A tolerance specifies an allowable deviation

from a target value where a characteristic is

still acceptable.

T ARGET

-1 +1

Lower specification

limit (LSL)

Upper specification

limit (USL)

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Ch04 Metrics