6. Work Study and Measurement

8/8/2019 6. Work Study and Measurement

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Work StudyWork Study



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Why do We Care About Productivity?Why do We Care About Productivity?Why do We Care About Productivity?Why do We Care About Productivity?

Without productivity improvement, businesses do notWithout productivity improvement, businesses do not

survive in a global economysurvive in a global economy..

Higher productivity means higher standard of livingHigher productivity means higher standard of living..



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Ways to Increase ProductivityWays to Increase ProductivityWays to Increase ProductivityWays to Increase Productivity

Increase output using the same or a lesser amount of Increase output using the same or a lesser amount of

resourceresource..

Reduce amount of resource used while keepingReduce amount of resource used while keepingoutput constant or increasing itoutput constant or increasing it..



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Impact of Price/Cost Change on ProductivityImpact of Price/Cost Change on ProductivityImpact of Price/Cost Change on ProductivityImpact of Price/Cost Change on Productivity

When the cost of a resource increases and profit is toWhen the cost of a resource increases and profit is to

remain the same, some combination of the followingremain the same, some combination of the following

must occur must occur::

output is increasedoutput is increased

price price of output is increasedof output is increased



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Factors used forFactors used for

Measuring ProductivityMeasuring Productivity

Factors used forFactors used for

Measuring ProductivityMeasuring Productivity

CapitalCapital -- Number Number of products producedof products produced

divideddivided by asset value by asset value

MaterialsMaterials -- Number Number of products producedof products produced

divideddivided by by amountamount spent on materialsspent on materials Direct Labor Direct Labor -- Number of products produced Number of products produced

divideddivided by direct labor by direct labor--hourshours

OverheadOverhead -- Number Number of products producedof products produced

divideddivided by by amountamount spent onspent on overheadsoverheads



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Work studyWork studyWork studyWork study

Work study is a study of better ways of doing things andWork study is a study of better ways of doing things anddevelops controls by setting standards with respect todevelops controls by setting standards with respect totime.time.

³Methods study´ is the means of improving ways and³Methods study´ is the means of improving ways andmeans of doing things.means of doing things.

The primary purpose of improving µmethods¶ is to saveThe primary purpose of improving µmethods¶ is to savetime and thus effort of time and thus effort of labour labour and machinery.and machinery.

Thus, a measurement of work involved in any job andThus, a measurement of work involved in any job andsetting up standards of time for control purposes normallysetting up standards of time for control purposes normallyexpected is necessary.expected is necessary.



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Foundation of work studyFoundation of work studyFoundation of work studyFoundation of work study

Dr. Taylor¶s conclusion from various experimentsDr. Taylor¶s conclusion from various experiments

was:was:

³The greatest production results when each worker is³The greatest production results when each worker is

given a definite task to be performed in a definitegiven a definite task to be performed in a definitetime in a definite manner.´time in a definite manner.´



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Method StudyMethod StudyMethod StudyMethod Study

The main components of method study areThe main components of method study are

Gaining information about and understanding theGaining information about and understanding the

process, men carrying the process and their work, process, men carrying the process and their work,

machines carrying out the work, tools and workingmachines carrying out the work, tools and workingconditions.conditions.

AnalyseAnalyse the obtained information criticallythe obtained information critically

Chalk out improved alternative methodsChalk out improved alternative methods

Check acceptance and followCheck acceptance and follow--up implementationup implementation

ReRe--evaluate and maintain the method after evaluate and maintain the method after

production is undertaken production is undertaken



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Benefits of methods studyBenefits of methods studyBenefits of methods studyBenefits of methods study

Improved cost performanceImproved cost performance

Improved time performanceImproved time performance

Improved worker satisfactionImproved worker satisfaction

ImprovedImproved standardisationstandardisation of productsof products



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Work MeasurementWork MeasurementWork MeasurementWork Measurement

Work measurementWork measurement refers to the process of estimatingrefers to the process of estimating

the amount of worker time required to produce onethe amount of worker time required to produce one

unit of outputunit of output..

A goal of work measurement is to develop labor A goal of work measurement is to develop labor

standards that can be used for planning andstandards that can be used for planning and

controlling operations.controlling operations.



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Labor StandardsLabor StandardsLabor StandardsLabor Standards

AA labour labour standardstandard is the number of worker is the number of worker--minutesminutesrequired to complete an element, operation, or required to complete an element, operation, or product under ordinary operating conditions product under ordinary operating conditions..

Labour Labour standards are used to plan and controlstandards are used to plan and controloperations.operations.

Labour Labour standards help in determiningstandards help in determining labour labour costscostsand finally help in pricing new products.and finally help in pricing new products.

Labour Labour standards also aid in incentive pay systems.standards also aid in incentive pay systems.



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Labor StandardsLabor StandardsLabor StandardsLabor Standards

A labor standard can be determined using one or A labor standard can be determined using one or

more of the following approaches:more of the following approaches:

Time studyTime study

Work samplingWork sampling Predetermined time standardsPredetermined time standards

HistoricalHistorical standardsstandards

Supervisor estimatesSupervisor estimates



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Time studyTime studyTime studyTime study

Time study is undertaken to set the standard times for Time study is undertaken to set the standard times for

work.work.

Basic systems of time study involveBasic systems of time study involve

Using a stop watchUsing a stop watch Using synthetic time standardsUsing synthetic time standards

Using statistical samplingUsing statistical sampling



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Time StudyTime StudyTime StudyTime Study

Suitable JobsSuitable Jobs

Job performed by a single worker in a fixed locationJob performed by a single worker in a fixed location

Job involves repetitive short cyclesJob involves repetitive short cycles

Job expected to continue unchanged for a long periodJob expected to continue unchanged for a long period Job produces large quantities of outputJob produces large quantities of output

Resulting time standard must be very accurateResulting time standard must be very accurate



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Time StudyTime StudyTime StudyTime Study

Analysts use stopwatches to time the operation beingAnalysts use stopwatches to time the operation being

performed by workers performed by workers

These observed times are then converted into labor These observed times are then converted into labor

standards expressedstandards expressed in minutes per unit of output for in minutes per unit of output for the operationthe operation



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Determining Labor StandardsDetermining Labor Standards

from Time Studiesfrom Time Studies



ObservedObserved

TimeTime

NormalNormal

TimeTime

StandardStandard

TimeTime

PerformancePerformance

RatingRating

Allowance Allowance

FractionFraction



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1.1. Break Break the operation down into basicthe operation down into basic taskstasks

2.2. Determine which cycle of operations are to be timed.Determine which cycle of operations are to be timed.

3.3. Observe and record the elapsed time for eachObserve and record the elapsed time for each of theof the

taskstasks4.4. For each task, estimate the observed worker¶sFor each task, estimate the observed worker¶s

performance rating performance rating. A rating of 1.00 indicates the. A rating of 1.00 indicates the

worker is working at normal speed.worker is working at normal speed.

5.5. Compute the allowance fraction for the operation.Compute the allowance fraction for the operation.(allowance are applied to compensate for personal time,(allowance are applied to compensate for personal time,

fatigue and unavoidable minor delays)fatigue and unavoidable minor delays)



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6.6. Compute theCompute the mean observed timemean observed time for each element:for each element:

(Sum of observed element times)(Sum of observed element times)

(Number of cycles timed)(Number of cycles timed)

7.7. Compute theCompute the element normal timeelement normal time for each element:for each element:

= (Mean observed time)= (Mean observed time) xx (Performance rating)(Performance rating)

==



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9.9. Compute theCompute the total normal timetotal normal time for the entirefor the entire

operation:operation:

= (Sum of element normal times for all elements)= (Sum of element normal times for all elements)

10.10. Compute theCompute the labor standardlabor standard for the operation:for the operation:

= (Total normal time)= (Total normal time) // (1(1 -- Allowance fraction)Allowance fraction)



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Example: Time Study ApproachExample: Time Study ApproachExample: Time Study ApproachExample: Time Study Approach

In a time study of a manufacturing operation, theIn a time study of a manufacturing operation, the

average time observed to complete a product was 8.6 average time observed to complete a product was 8.6

minutes. The performance rating applied to theminutes. The performance rating applied to the

observed worker was 0.95 and the allowance duringobserved worker was 0.95 and the allowance during

an 8an 8--hour shift was 12.5% or 60 minutes.hour shift was 12.5% or 60 minutes.

Compute the labor standard.Compute the labor standard.



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Example: Time Study ApproachExample: Time Study ApproachExample: Time Study ApproachExample: Time Study Approach

Observed timeObserved time = 8.6 minutes= 8.6 minutes Performance ratingPerformance rating = 0.95= 0.95

Allowance fractionAllowance fraction = 0.125= 0.125

Normal time = Observed time Normal time = Observed time xx Performance ratingPerformance rating

= 8.6 = 8.6 xx 0.950.95

= 8.17 minutes= 8.17 minutes

Standard Time = Normal time / (1Standard Time = Normal time / (1 -- Allowance)Allowance)

=8

.17

/ (1=8

.17

/ (1 -- .125).125)

= 8.17 / (0.875)= 8.17 / (0.875)

= 9.337 minutes= 9.337 minutes



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Uses of time samplingUses of time samplingUses of time samplingUses of time sampling

Aids in setting wages and incentivesAids in setting wages and incentives

Comparing work efficiency of workersComparing work efficiency of workers

Arriving at job schedules for planning productionArriving at job schedules for planning production

Manpower planningManpower planning Helps in product designHelps in product design



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Work SamplingWork SamplingWork SamplingWork Sampling

Work sampling samples the work Work sampling samples the work of one or moreof one or moreemployeesemployees randomly sampled at periodic intervalsrandomly sampled at periodic intervals

TheThe proportion of the total operation that is accounted proportion of the total operation that is accounted

for in one particular for in one particular activity is notedactivity is noted

The results of these studies are usedThe results of these studies are used to setto set labor labor

standardsstandards



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Elements

1 2 3 4 5 Sum Mean Rating

Normal

Print

first

page

.1 .09 .09 .08 .09 1

Collate papers .0

4.03

.04

.06

.05

.9

Print

second

page

.05 .06 .04 .07 .05 1

Collate

papers

.12 .10 .09 .08 .09 .9

Labour standard = total normal time / (1-Allowance time)



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Work SamplingWork SamplingWork SamplingWork Sampling


Job performed by a single worker in a fixed locationJob performed by a single worker in a fixed location

Job involves repetitive short cyclesJob involves repetitive short cycles

Job expected to be changed periodically as customer Job expected to be changed periodically as customer orders changeorders change

Job produces relatively small quantities of outputJob produces relatively small quantities of output

Resulting time standard used for accounting costResulting time standard used for accounting cost

standard, pricing analysis, and production planningstandard, pricing analysis, and production planning



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Example: Work SamplingExample: Work SamplingExample: Work SamplingExample: Work Sampling

A work sampling study was performed on anA work sampling study was performed on anelectronic assembly operation at OK Instruments.electronic assembly operation at OK Instruments.The study covered an 8The study covered an 8--hour shift with a singlehour shift with a singleworker. The results of the study were:worker. The results of the study were:

ActivityActivity % of Worker¶s Time% of Worker¶s Time

Assemble UnitsAssemble Units 8080

AllowancesAllowances 2020

If If the worker received a performance rating of 1.20the worker received a performance rating of 1.20on the Assemble Units activity and 400 units wereon the Assemble Units activity and 400 units wereassembled during the study, what is the labor standardassembled during the study, what is the labor standardfor this operation?for this operation?



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1) Compute the average time per assemble:1) Compute the average time per assemble:

= Total Minutes of AssemblyWork = Total Minutes of AssemblyWork

Number of Units Assembled Number of Units Assembled

= .8(480)/400 = .960 minutes per unit= .8(480)/400 = .960 minutes per unit

2) Compute the normal time per unit:2) Compute the normal time per unit:

= (Average Time per Unit)(Performance Rating)= (Average Time per Unit)(Performance Rating)

= .960(1.20) = 1.152 minutes per unit= .960(1.20) = 1.152 minutes per unit



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3) Compute the labor standard:3) Compute the labor standard:

= Normal Time/(1= Normal Time/(1 ± ± Allowance Fraction)Allowance Fraction)

= 1.152/(1= 1.152/(1 -- .20) = 1.44 minutes per unit.20) = 1.44 minutes per unit




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Predetermined Time StandardsPredetermined Time StandardsPredetermined Time StandardsPredetermined Time Standards


Job performed by many workers over a compact areaJob performed by many workers over a compact area

Tasks may involve little repetition, but if repetitiousTasks may involve little repetition, but if repetitious ± ±

the cycles are very longthe cycles are very long Workers must be observed by a single analystWorkers must be observed by a single analyst

A moderate degree of accuracy in the labor standardA moderate degree of accuracy in the labor standard

is desirable, but a time study is too costlyis desirable, but a time study is too costly

Only large elements of work need to be observedOnly large elements of work need to be observed

Little detail is needed in setting the time standardLittle detail is needed in setting the time standard



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Predetermined Time StandardsPredetermined Time StandardsPredetermined Time StandardsPredetermined Time Standards

Commonly used for new operations or new productsCommonly used for new operations or new products When labor standard must be determined in advanceWhen labor standard must be determined in advance

of performing an operationof performing an operation

Utilize data that have been historically developed for Utilize data that have been historically developed for

basic body movements, elements of operations, and basic body movements, elements of operations, andentire operationsentire operations

Many predetermined time standard systems are used:Many predetermined time standard systems are used: Work factor Work factor MethodsMethods--time measurement (MTM)time measurement (MTM) Basic motion time (BMT)Basic motion time (BMT) studystudy



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Methods time measurementMethods time measurementMethods time measurementMethods time measurement

The basic MTM approach is to classify human work The basic MTM approach is to classify human work motions into certain fixed standard categories such asmotions into certain fixed standard categories such as

Reach, Move, Turn, Apply pressure, Grasp, EyeReach, Move, Turn, Apply pressure, Grasp, Eye--

motions, bodymotions, body--leg and foot motions.leg and foot motions.

MTM association has done extensive studies on handMTM association has done extensive studies on hand

and body motions and arrived at normal times for and body motions and arrived at normal times for

each of these subeach of these sub--classes of motions.classes of motions.

These are preThese are pre--determined times for motions whichdetermined times for motions whichhelp to set a time standard for a job.help to set a time standard for a job.



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Merits and demeritsMerits and demeritsMerits and demeritsMerits and demerits

It avoids performanceIt avoids performancerating which is subjectiverating which is subjective

It can be used for jobs thatIt can be used for jobs that

are still in the planningare still in the planning

stagestage

There is a definiteThere is a definite

breakdown of motion breakdown of motion

elementselements

A detailed method studyA detailed method study

and work study areand work study are

combined into onecombined into one

It is applicable only for It is applicable only for hand, body and eyehand, body and eye

motionsmotions

Process times for other Process times for other

activities have to beactivities have to beestablished using other established using other

methodsmethods

Ordinary workers areOrdinary workers are

baffled by lengthy details baffled by lengthy details

Detailed analysis involvedDetailed analysis involved

isis time consumingtime consuming



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Subjective MethodsSubjective MethodsSubjective MethodsSubjective Methods


Any job or group of jobs in which:Any job or group of jobs in which:

Very accurate labor standards are not required, or Very accurate labor standards are not required, or

The cost of time study, predetermined timeThe cost of time study, predetermined timestandards, and work sampling is prohibitivestandards, and work sampling is prohibitive



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Appropriate work measurement techniqueAppropriate work measurement techniqueAppropriate work measurement techniqueAppropriate work measurement technique

A job performed by a single worker in a fixed location. Involves shortA job performed by a single worker in a fixed location. Involves shortrepetitive cycles and is expected to continue relatively unchanged for longrepetitive cycles and is expected to continue relatively unchanged for long periods while producing large quantities of outputs. Very accurate periods while producing large quantities of outputs. Very accurate labour labour standards are requiredstandards are required

A job performed by a single worker in a fixed location. Involves shortA job performed by a single worker in a fixed location. Involves short

repetitive cycles and changes when customers orders for relatively smallrepetitive cycles and changes when customers orders for relatively smallquantities of products change. Labor standards are used for accounting costquantities of products change. Labor standards are used for accounting coststandards, pricing analysis and production planningstandards, pricing analysis and production planning

A job performed by many workers over a compact area. The tasks involveA job performed by many workers over a compact area. The tasks involvelittle repetition; if repetitive they involve long cycles. Workers must belittle repetition; if repetitive they involve long cycles. Workers must beobserved by a single analyst. Moderate accuracy required. Little detail isobserved by a single analyst. Moderate accuracy required. Little detail is

needed in setting standards.needed in setting standards.

Any job or groups of jobs in which very accurate standards are not requiredAny job or groups of jobs in which very accurate standards are not requiredor where cost of time study and other methods is prohibitive.or where cost of time study and other methods is prohibitive.



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Learning CurvesLearning CurvesLearning CurvesLearning Curves

At the start of production runs:At the start of production runs:

Workers are unfamiliar with their tasksWorkers are unfamiliar with their tasks

Time it takes to produce the first few units is highTime it takes to produce the first few units is high

As the workers learn their tasks:As the workers learn their tasks: Their output per day increases up to a pointTheir output per day increases up to a point

Then their output levels off to a rather constant rateThen their output levels off to a rather constant rate



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Most aircraft manufacturing tasks experience an 80% Most aircraft manufacturing tasks experience an 80% learning ratelearning rate

Labor Labor--hours required to assemble an aircraft ishours required to assemble an aircraft is

reduced by a factor of 0.8 as the production quantityreduced by a factor of 0.8 as the production quantity

doublesdoubles

If first aircraft assembled requires 100 labor If first aircraft assembled requires 100 labor--hourshours

Second aircraft would require 80 labor Second aircraft would require 80 labor--hourshours

Fourth aircraft would require 64 labor Fourth aircraft would require 64 labor--hourshours

Eighth aircraft would require 51.2 labor Eighth aircraft would require 51.2 labor--hourshours

« and so on« and so on



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10 20 30 40 50 60 70 80 90 100 11010 20 30 40 50 60 70 80 90 100 110 120 130120 130

2020

8080

4040

100100

6060

Unit Number (Unit Number (nn))

120120

Labor Labor--Hours for Hours for nnth Unitth Unit

Aircraft AssemblyAircraft Assembly

80% Learning Curve80% Learning Curve



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UsesUses and limitationsand limitations

Products and services tend to be customProducts and services tend to be custom designeddesigned

requiring the workers to start from the scratchrequiring the workers to start from the scratch

Batches tend to beBatches tend to be small and hence performancesmall and hence performanceimproves dramatically from the first to the last unitimproves dramatically from the first to the last unit

Product/services tend to be complex.... learningProduct/services tend to be complex.... learning

occurs quicklyoccurs quickly

6. Work Study and Measurement

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