heizer supp 10

7/24/2019 Heizer Supp 10

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2008 Prentice Hall, Inc. S10 1

OperationsManagementSupplement 10 Supplement 10 Work MeasurementWork Measurement

PowerPoint presentation to accompanyPowerPoint presentation to accompany

Heizer/RenderHeizer/Render

Principles o Operations Management! "ePrinciples o Operations Management! "e

Operations Management! #eOperations Management! #e


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OutlineOutline

$a%or Standards and Work$a%or Standards and WorkMeasurementMeasurement

Historical &'perienceHistorical &'perience (ime Studies(ime Studies

Predetermined (imePredetermined (ime

StandardsStandards

Work SamplingWork Sampling


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$earning O%)ecti*es$earning O%)ecti*es

W+en you complete t+is supplementW+en you complete t+is supplementyou s+ould %e a%le to,you s+ould %e a%le to,

-dentiy our ways o esta%lis+ing la%or-dentiy our ways o esta%lis+ing la%orstandardsstandards

.ompute t+e normal and standard.ompute t+e normal and standardtimes in a time studytimes in a time study

ind t+e proper sample size or a timeind t+e proper sample size or a timestudystudy


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$earning O%)ecti*es$earning O%)ecti*es

W+en you complete t+is supplementW+en you complete t+is supplementyou s+ould %e a%le to,you s+ould %e a%le to,

&'plain +ow predetermined time&'plain +ow predetermined timestandards and (Ms are used in workstandards and (Ms are used in workmeasurementmeasurement

pply t+e i*e steps o work samplingpply t+e i*e steps o work sampling


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$a%or Standards and Work$a%or Standards and Work

MeasurementMeasurement Started early in t+e 20t+ centuryStarted early in t+e 20t+ century

-mportant to %ot+ manuacturing-mportant to %ot+ manuacturingand ser*ice organizationsand ser*ice organizations

3ecessary or determining staing3ecessary or determining staing

re4uirementsre4uirements -mportant to la%or incenti*e-mportant to la%or incenti*e

systemssystems


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Meaningul Standards HelpMeaningul Standards Help

5etermine5etermine1616 $a%or content o items produced$a%or content o items produced

2626 Staing needsStaing needs7676 .ost and time estimates.ost and time estimates

8686 .rew size and work %alance.rew size and work %alance

9696 &'pected production&'pected production:6:6 ;asis o wage incenti*e plans;asis o wage incenti*e plans

"6"6 &iciency o employees&iciency o employees


7/39 2008 Prentice Hall, Inc. S10 7

$a%or Standards$a%or Standards

May %e set in our ways,May %e set in our ways,

1616 Historical e'perienceHistorical e'perience

2626 (ime studies(ime studies

7676 Predetermined time standardsPredetermined time standards

8686 Work samplingWork sampling



Historical &'perienceHistorical &'perience

How t+e task was perormed lastHow t+e task was perormed lasttimetime

&asy and ine'pensi*e&asy and ine'pensi*e

5ata a*aila%le rom production5ata a*aila%le rom productionrecords or time cardsrecords or time cards

5ata is not o%)ecti*e and may %e5ata is not o%)ecti*e and may %einaccurateinaccurate

3ot recommended3ot recommended



(ime Studies(ime Studies

-n*ol*es timing a sample o a-n*ol*es timing a sample o aworker




1616 5eine t+e task to %e studied5eine t+e task to %e studied

2626 5i*ide t+e task into precise5i*ide t+e task into preciseelementselements

7676 5ecide +ow many times to measure5ecide +ow many times to measuret+e taskt+e task

8686 (ime and record element times and(ime and record element times andrating o perormancerating o perormance




9696 .ompute a*erage o%ser*ed time.ompute a*erage o%ser*ed time

*erage*erageo%ser*edo%ser*ed

timetime

Sum o t+e times recordedSum o t+e times recorded

to perorm eac+ elementto perorm eac+ element3um%er o o%ser*ations3um%er o o%ser*ations

==

:6:6 5etermine perormance rating5etermine perormance ratingand normal timeand normal time

3ormal time = '3ormal time = '*erage*erageo%ser*edo%ser*ed

timetime

PerormancePerormancerating actorrating actor




"6"6dd t+e normal times or eac+dd t+e normal times or eac+element to de*elop t+e total normalelement to de*elop t+e total normal

time or t+e tasktime or t+e task

>6>6 .ompute t+e standard time.ompute t+e standard time

Standard time =Standard time = (otal normal time(otal normal time1 -1 -llowance actorllowance actor



Rest llowancesRest llowances

Personal time allowancePersonal time allowance

8? @ "? o total time or use o8? @ "? o total time or use o

restroom! water ountain! etc6restroom! water ountain! etc6 5elay allowance5elay allowance

;ased upon actual delays t+at occur;ased upon actual delays t+at occur

atigue allowanceatigue allowance ;ased on our knowledge o +uman;ased on our knowledge o +uman

energy e'penditureenergy e'penditure




1616 .onstant allowance.onstant allowance

ABAB Personal allowance CCCCC666Personal allowance CCCCC666 55

A;BA;B ;asic atigue allowance CCCC;asic atigue allowance CCCC 44

2626 Daria%le allowances,Daria%le allowances,

ABAB Standing allowance CCCCCCStanding allowance CCCCCC 22

A;BA;B%normal position%normal position

AiBAiB wkward A%endingB CCCCwkward A%endingB CCCC 22

AiiBAiiB Dery awkward Alying!Dery awkward Alying!stretc+ingB CCCCCCCCstretc+ingB CCCCCCCC 77

Figure S10.1Figure S10.1




A.BA.B se o orce or muscular energy inse o orce or muscular energy inliting! pulling! pus+ingliting! pulling! pus+ing

Weig+t lited ApoundsBWeig+t lited ApoundsB

20 CCCCCCCCCCCCCC20 CCCCCCCCCCCCCC 33

80CCCCCCCCCCCCCC680CCCCCCCCCCCCCC6 99

:0CCCCCCCCCCCCCC6:0CCCCCCCCCCCCCC6 1717

A5BA5B ;ad lig+t,;ad lig+t,

AiBAiB Well %elow recommendedC6Well %elow recommendedC6 22

AiiBAiiB Euite inade4uateCCCCC6Euite inade4uateCCCCC6 55Figure S10.1Figure S10.1




A&BA&Btmosp+eric conditionstmosp+eric conditionsA+eat and +umidityB CCCCCA+eat and +umidityB CCCCC 0-100-10

ABAB .lose attention,.lose attention,

AiB ine or e'actingCCCCCC66AiB ine or e'actingCCCCCC66 22

AiiB Dery ine or *ery e'actingCCAiiB Dery ine or *ery e'actingCC 55

AFBAFB 3oise le*el,3oise le*el,

AiB -ntermittentGloudCCCCC66AiB -ntermittentGloudCCCCC66 22

AiiB -ntermittentG*ery loudAiiB -ntermittentG*ery loud or +ig+@pitc+edCCCCCC666 or +ig+@pitc+edCCCCCC666 55





AHBAHB Mental strain,Mental strain,

AiB .omple' or wide spanAiB .omple' or wide span

o attention6CCCCCCCC66 o attention6CCCCCCCC66 44AiiB Dery comple'CCCCCCC66AiiB Dery comple'CCCCCCC66 88

A-BA-B (ediousness,(ediousness,

AiB (ediousCCCC66CCCCCCAiB (ediousCCCC66CCCCCC 22AiiB Dery tedious6CCCCCCCCAiiB Dery tedious6CCCCCCCC 55




(ime Study &'ample S1(ime Study &'ample S1

*erage o%ser*ed time*erage o%ser*ed time = 4.0= 4.0minutesminutesWorker ratingWorker rating = 85%= 85%llowance actorllowance actor = 13%= 13%

3ormal time = A*erage o%ser*ed timeB ' ARating actorB3ormal time = A*erage o%ser*ed timeB ' ARating actorB

= (4.0)(.85)= (4.0)(.85)

= 3.4= 3.4minutesminutes

Standard time = = =Standard time = = =3ormal time3ormal time

1 -1 -llowance actorllowance actor

3.43.4

1 - .131 - .133.43.4

.87.87

= 3.9= 3.9minutesminutes


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llowance actorllowance actor = 15%= 15%

PerormancePerormanceo% &lemento% &lement 11 22 77 88 99 RatingRating

ABAB .ompose and type letter.ompose and type letter 88 1010 99 21*21* 1111 120%120%

A;BA;B (ype en*elope address(ype en*elope address 22 33 22 11 33 105%105%

A.BA.B Stu! stamp! seal! andStu! stamp! seal! and 22 11 5*5* 22 11 110%110% sort en*elopes sort en*elopes

.ycle O%ser*ed Ain minutesB.ycle O%ser*ed Ain minutesB

1616 5elete unusual or nonrecurring o%ser*ations Amarked wit+ IB5elete unusual or nonrecurring o%ser*ations Amarked wit+ IB2626 .ompute a*erage times or eac+ element.ompute a*erage times or eac+ element

*erage time or *erage time or = (8 + 10 + 9 + 11)/4 = 9.5= (8 + 10 + 9 + 11)/4 = 9.5minutesminutes

*erage time or ;*erage time or ; = (2 + 3 + 2 + 1 + 3)/5 = 2.2= (2 + 3 + 2 + 1 + 3)/5 = 2.2 minutesminutes

*erage time or .*erage time or . = (2 + 1 + 2 + 1)/4 = 1.5= (2 + 1 + 2 + 1)/4 = 1.5 minutesminutes


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7676 .ompute t+e normal time or eac+ element.ompute t+e normal time or eac+ element

3ormal time or 3ormal time or = (9.5)(1.2) = 11.4= (9.5)(1.2) = 11.4minutesminutes3ormal time or ;3ormal time or ; = (2.2)(1.05) = 2.31= (2.2)(1.05) = 2.31minutesminutes

3ormal time or .3ormal time or . = (1.5)(1.10) = 1.65= (1.5)(1.10) = 1.65minutesminutes

3ormal time = A*erage o%ser*ed timeB ' ARatingB3ormal time = A*erage o%ser*ed timeB ' ARatingB

8686

dd t+e normal times to ind t+e total normal timedd t+e normal times to ind t+e total normal time

(otal normal time(otal normal time = 11.40 + 2.31 + 1.65 = 15.36= 11.40 + 2.31 + 1.65 = 15.36minutesminutes


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9696 .ompute t+e standard time or t+e )o%.ompute t+e standard time or t+e )o%

Standard time =Standard time =(otal normal time(otal normal time

1 -1 -llowance actorllowance actor

= = 18.07= = 18.07minutesminutes15.3615.36

1 - .151 - .15


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5etermine Sample Size5etermine Sample Size

How accurate we want to %eHow accurate we want to %e

(+e desired le*el o conidence(+e desired le*el o conidence

How muc+ *ariation e'ists wit+inHow muc+ *ariation e'ists wit+int+e )o% elementst+e )o% elements


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Re4uired sample size = n =Re4uired sample size = n =

22zszs

+'+'

w+erew+ere ++ == accuracy le*el desired inaccuracy le*el desired inpercent o t+e )o% element e'pressed aspercent o t+e )o% element e'pressed asa decimala decimal

zz == num%er o standardnum%er o standardde*iations re4uired or t+e desired le*elde*iations re4uired or t+e desired le*elo conidenceo conidence

ss == standard de*iation o t+estandard de*iation o t+einitial sampleinitial sample

'' == mean o t+e initial samplemean o t+e initial sample


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Re4uired sample size = n =Re4uired sample size = n =

22zszs

+'+'

w+erew+ere ++ == accuracy le*el desired inaccuracy le*el desired inpercent o t+e )o% element e'pressed aspercent o t+e )o% element e'pressed asa decimala decimal

zz == num%er o standardnum%er o standardde*iations re4uired or t+e desired le*elde*iations re4uired or t+e desired le*elo conidenceo conidence

ss == standard de*iation o t+estandard de*iation o t+einitial sampleinitial sample

'' == mean o t+e initial samplemean o t+e initial sample

5esired.onidence

A?B

z DalueAstandard de*iation re4uired or

desired le*el o conidenceB

90.0 1.65

95.0 1.96

95.45 2.00

99.0 2.58

99.73 3.00

.ommon z Dalues

Tabe S10.1


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5esired accuracy wit+5esired accuracy wit+ 5%5%.onidence le*el.onidence le*el = 95%= 95%Sample standard de*iationSample standard de*iation = 1.0= 1.0Sample meanSample mean = 3.00= 3.00

n =n =

22zszs

+'+'

nn = = 170.74 ! 171= = 170.74 ! 171

221.96 " 1.01.96 " 1.0

.05 " 3.05 " 3

++ = .05= .05 '' = 3.00= 3.00 ss = 1.0= 1.0

zz= 1.96 (= 1.96 (romrom Tabe S10.1Tabe S10.1or ppendi' -or ppendi' -))


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n =n =

22zszs

ee

- desired accuracy + is e'pressed as an a%solute- desired accuracy + is e'pressed as an a%soluteamount! su%stitute e or +'! w+ere e is t+eamount! su%stitute e or +'! w+ere e is t+e

a%solute amount o accepta%le errora%solute amount o accepta%le error

DariationsDariations

W+en t+e standard de*iation s is not pro*ided!W+en t+e standard de*iation s is not pro*ided!it must %e computedit must %e computed

s = =s = =JJA'A'ii@ 'B@ 'B2

2 JJA&ac+ sample o%ser*ation @ 'BA&ac+ sample o%ser*ation @ 'B22

nn - 1- 1 3um%er in sample3um%er in sample- 1- 1


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3ew (ools3ew (ools

Wit+ P5 sotware! you can studyWit+ P5 sotware! you can studyelements! time! perormance rate! andelements! time! perormance rate! andstatistical conidence inter*als can %estatistical conidence inter*als can %e

created!created!edited!edited!managed!managed!and loggedand logged

Reduces orReduces oreliminateseliminatest+e needt+e needor data entryor data entry


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Predetermined (imePredetermined (ime

StandardsStandards 5i*ide manual work into small %asic5i*ide manual work into small %asic

elements t+at +a*e esta%lis+ed timeselements t+at +a*e esta%lis+ed times

.an %e done in a la%oratory away rom.an %e done in a la%oratory away romt+e actual production operationt+e actual production operation

.an %e set %eore.an %e set %eoret+e work is actuallyt+e work is actually

perormedperormed

3o perormance3o perormanceratings are necessaryratings are necessary


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M(M (a%leM(M (a%le



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M(M &'ampleM(M &'ample

Weig+t @ less t+an 2 poundsWeig+t @ less t+an 2 pounds

.onditions o F&( @ easy.onditions o F&( @ easy

Place accuracy @ appro'imatePlace accuracy @ appro'imate

5istance range @ > to 20 inc+es5istance range @ > to 20 inc+es

&lement 5escription&lement 5escription &lement&lement (ime(ime

Fet tu%e rom rackFet tu%e rom rack 22 3535

Fet stopper! place on counterFet stopper! place on counter 22 3535

Fet centriuge tu%e! place at sample ta%leFet centriuge tu%e! place at sample ta%le 5252 4545

Pour A7 secondsBPour A7 secondsB P(P( 8383

Place tu%es in rack AsimoBPlace tu%es in rack AsimoB P.2P.2 4040

(otal (M(otal (M 238238

.0006 " 238 =.0006 " 238 =(otal standard minutes(otal standard minutes = .14= .14

Tabe S10.2Tabe S10.2


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&stimates percent o time a worker&stimates percent o time a workerspends on *arious tasksspends on *arious tasks

Re4uires random o%ser*ations toRe4uires random o%ser*ations torecord worker acti*ityrecord worker acti*ity

5etermines +ow employees allocate5etermines +ow employees allocatet+eir timet+eir time

.an %e used to set staing le*els!.an %e used to set staing le*els!reassign duties! estimate costs! andreassign duties! estimate costs! andset delay allowancesset delay allowances


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d*antages o work samplingd*antages o work sampling

$ess e'pensi*e t+an time study$ess e'pensi*e t+an time study

O%ser*ers need little trainingO%ser*ers need little trainingStudies can %e delayed or interruptedStudies can %e delayed or interrupted

wit+ little impact on resultswit+ little impact on results

Worker +as littleWorker +as littlec+ance to aectc+ance to aectresultsresults

$ess intrusi*e$ess intrusi*e


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5isad*antages o work sampling5isad*antages o work sampling

5oes not di*ide work elements as5oes not di*ide work elements as

completely as time studycompletely as time study.an yield %iased results i o%ser*er.an yield %iased results i o%ser*er

does not ollow random patterndoes not ollow random pattern

$ess accurate! especially w+en$ess accurate! especially w+en)o% element times are s+ort)o% element times are s+ort



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1616 (ake a preliminary sample to o%tain(ake a preliminary sample to o%tainestimates o parameter *aluesestimates o parameter *alues

2626 .ompute t+e sample size re4uired.ompute t+e sample size re4uired7676 Prepare a sc+edule or randomPrepare a sc+edule or random

o%ser*ations at appropriate timeso%ser*ations at appropriate times

8686 O%ser*e and record worker acti*itiesO%ser*e and record worker acti*ities

9696 5etermine +ow workers spend t+eir5etermine +ow workers spend t+eirtimetime


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5etermining t+e sample size5etermining t+e sample size

n =n =

zz22pp(1 -(1 -pp))

++22

w+erew+ere nn == re4uired sample sizere4uired sample size

zz == standard normal de*iatestandard normal de*iate

or desired conidence le*elor desired conidence le*elpp == estimated *alue oestimated *alue osample proportionsample proportion

++ == accepta%le error le*el inaccepta%le error le*el in

percentpercent


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Work Sampling &'ampleWork Sampling &'ample

Wants employees idle 29? o t+e timeWants employees idle 29? o t+e time

Sample s+ould %e accurate wit+in 7?Sample s+ould %e accurate wit+in 7?

Wants to +a*e #9689? conidence in t+e resultsWants to +a*e #9689? conidence in t+e results

n =n = zz22

pp(1 -(1 -pp))++22

w+erew+ere nn == re4uired sample sizere4uired sample size

zz == 22or aor a 95.45%95.45%conidenceconidence

le*elle*el

pp == estimate o idle proportionestimate o idle proportion

= 25% = .25= 25% = .25

++ == accepta%le error oaccepta%le error o 3% = .3% = .

0303nn = = 833= = 833 o%ser*ationso%ser*ations(2)(2)22(.25)(.75)(.25)(.75)

(.03)(.03)22


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Work Sampling &'ampleWork Sampling &'ample

3o6 o3o6 oO%ser*ationsO%ser*ations cti*itycti*ity

485485 On t+e p+one or meeting wit+ a welare clientOn t+e p+one or meeting wit+ a welare client

126126 -dle-dle

6262 Personal timePersonal time

2323 5iscussions wit+ super*isor5iscussions wit+ super*isor

137137 iling! meeting! and computer data entryiling! meeting! and computer data entry

833833

ll %ut idle and personal time are work related6ll %ut idle and personal time are work related6

Percentage idle timePercentage idle time = (126 + 62)/833 = 22.6%.= (126 + 62)/833 = 22.6%.

Since t+is is less t+an t+e target *alue oSince t+is is less t+an t+e target *alue o 25%#25%#t+e workload needs to %e ad)usted6t+e workload needs to %e ad)usted6


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Work Sampling (imeWork Sampling (ime

StudiesStudiesSalespeopleSalespeople


(elep+one(elep+onesalessales12?12?

(elep+one(elep+onewit+in irmwit+in irm

17?17?

$unc+ and$unc+ andpersonalpersonal

10?10?

MeetingsMeetingsand ot+erand ot+er

>?>?

Paperwork1"?

(ra*el20?

Sales inperson

20?


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Work Sampling (imeWork Sampling (ime

StudiesStudies


Producti*ework

:"?

Startup/pep talkStartup/pep talk7?7?

;reaks and lunc+;reaks and lunc+

10?10?5ead time5ead time

%etween tasks%etween tasks17?17?

.leanup.leanup7?7?

nsc+eduled tasksnsc+eduled tasksand downtimeand downtime

8?8?

ssem%ly@$inessem%ly@$ine&mployees&mployees

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