Work Measure

8/14/2019 Work Measure

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Work Measurement


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Work Measurement

application of techniques designed to

establish the time for a qualified worker tocarry out a specified job at a defined level

of performance


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Why use Work Measurement

Set time standards for a job

Schedule work and allocate capacity

Labor content of items producedLabor content of items produced

Staffing needsStaffing needsCost and time estimatesCost and time estimates

Crew size and work balanceCrew size and work balance

Expected productionExpected production

Basis of wage incentive plansBasis of wage incentive plans

Efficiency of employeesEfficiency of employees


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Basic Procedure

Select

Record

Examine

Measure

Compile Define


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TechniquesTechniques

DirectDirect

Time studyTime study

Work samplingWork sampling

IndirectIndirect

Predetermined motion-time data systems (PTMS)Predetermined motion-time data systems (PTMS)

Elemental dataElemental data


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Time Study

work measurement technique for recording

the times and rates of working for the

elements of a specified job carried outunder specified conditions, and for

analysing the data so as to obtain the time

necessary for carrying out the job at adefined level of performance


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Rating

assessment of the workers rate of working

relative to the observers concept of the rate

corresponding to standard pace usually expressed in decimal form

a person working 10% faster than normal

would have a Performance Rating of 1.10 or110% of NT

working 10% slower, 0.90 or 90% of NT


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Time StudyTime Study

Involves timing a sample of a workersInvolves timing a sample of a workersperformance and using it to set a standardperformance and using it to set a standard

Requires trained and experiencedRequires trained and experiencedobserversobservers

Cannot be set before the work isCannot be set before the work isperformedperformed


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1.1. Define the task to be studiedDefine the task to be studied

2.2. Divide the task into precise elementsDivide the task into precise elements

3.3. Decide how many times to measure theDecide how many times to measure thetasktask

4.4. Time and record element times and ratingTime and record element times and ratingof performanceof performance


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5.5. Compute average observed timeCompute average observed time

AverageAverageobservedobservedtimetime

Sum of the times recorded toSum of the times recorded to

perform each elementperform each elementNumber of observationsNumber of observations

==

6.6. Determine performance rating andDetermine performance rating andnormal timenormal time

Normal time =Normal time =AverageAverageobservedobserved

timetime

PerformancePerformancerating factorrating factor

xx


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7.7. Add the normal times for each element toAdd the normal times for each element todevelop the total normal time for the taskdevelop the total normal time for the task

8.8. Compute the standard timeCompute the standard time

Standard time =Standard time = Total normal timeTotal normal time1 - Allowance factor1 - Allowance factor

Standard time = NT(1 + Allowance factor)Standard time = NT(1 + Allowance factor)



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Allowances

Personal

Needs

Basic

Fatigue

FixedAllowances

VariableAllowances

Relaxation

Contingency

Policy

Special

Total

Allowances

Stress & Strain

environmental


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Time Study Example 1

You want to determine the standard time forYou want to determine the standard time for

a job. The employee selected has produceda job. The employee selected has produced

20 units of product in an 8 hour day. You20 units of product in an 8 hour day. You

estimate that the employee worked about 10estimate that the employee worked about 10percent faster than what is a normal pacepercent faster than what is a normal pace

for the job. Allowances for the jobfor the job. Allowances for the job

represent 25 percent of the normal time.represent 25 percent of the normal time. What are the normal and standard times forWhat are the normal and standard times for

this job?this job?


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Time Study Example 1

Normal time = Time worked x (Perf. rating)

Number of units produced

= (480 minutes/20) x (1.10)

= 26.4 minutes

Standard time = NT (1+ Allowances)

= (26.4) * (1+0.25)

= 33 minutes


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Time Study Example 2Time Study Example 2

Average observed time = 4.0 minutesAverage observed time = 4.0 minutesWorker rating = 85%Worker rating = 85%Allowance factor = 13% of total work periodAllowance factor = 13% of total work period

Normal time = (Average observed time) x (Rating factor)Normal time = (Average observed time) x (Rating factor)

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

= 3.4 minutes= 3.4 minutes

Standard time = = =Standard time = = =Normal timeNormal time

1 - Allowance factor1 - Allowance factor

3.43.4

1 - .131 - .133.43.4

.87.87

= 3.9 minutes= 3.9 minutes


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Allowance factor = 15% of total timeAllowance factor = 15% of total time

PerformancePerformanceJob ElementJob Element 11 22 33 44 55 RatingRating

(A)(A) Compose and type letterCompose and type letter 88 1010 99 21*21* 1111 120%120%

(B)(B) Type envelope addressType envelope address 22 33 22 11 33 105%105%

(C)(C) Stuff, stamp, seal, andStuff, stamp, seal, and 22 11 5*5* 22 11 110%110%sort envelopessort envelopes

Cycle Observed (in minutes)Cycle Observed (in minutes)

1.1. Delete unusual or nonrecurring observations (marked with *)Delete unusual or nonrecurring observations (marked with *)2.2. Compute average times for each elementCompute average times for each element

Average time for A = (8 + 10 + 9 + 11)/4 = 9.5 minutesAverage time for A = (8 + 10 + 9 + 11)/4 = 9.5 minutes

Average time for B = (2 + 3 + 2 + 1 + 3)/5 = 2.2 minutesAverage time for B = (2 + 3 + 2 + 1 + 3)/5 = 2.2 minutes

Average time for C = (2 + 1 + 2 + 1)/4 = 1.5 minutesAverage time for C = (2 + 1 + 2 + 1)/4 = 1.5 minutes


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3.3. Compute the normal time for each elementCompute the normal time for each element

Normal time for A = (9.5)(1.2) = 11.4 minutesNormal time for A = (9.5)(1.2) = 11.4 minutesNormal time for B = (2.2)(1.05) = 2.31 minutesNormal time for B = (2.2)(1.05) = 2.31 minutes

Normal time for C = (1.5)(1.10) = 1.65 minutesNormal time for C = (1.5)(1.10) = 1.65 minutes

Normal time = (Average observed time) x (Rating)Normal time = (Average observed time) x (Rating)

4.4. Add the normal times to find the total normal timeAdd the normal times to find the total normal time

Total normal time = 11.40 + 2.31 + 1.65 = 15.36 minutesTotal normal time = 11.40 + 2.31 + 1.65 = 15.36 minutes



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5.5. Compute the standard time for the jobCompute the standard time for the job

Standard time =Standard time =Total normal timeTotal normal time

1 - Allowance factor1 - Allowance factor

= = 18.07 minutes= = 18.07 minutes15.3615.36

1 - .151 - .15



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Determine Sample SizeDetermine Sample Size

How accurate we want to beHow accurate we want to be

The desired level of confidenceThe desired level of confidence

How much variation exists within the jobHow much variation exists within the job

elementselements


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Required sample size = n =Required sample size = n =

22zszs

hxhx

wherewhere hh == accuracy level desired in percentaccuracy level desired in percentof the job element expressed as a decimalof the job element expressed as a decimal

zz == number of standard deviationsnumber of standard deviationsrequired for the desired level of confidencerequired for the desired level of confidence

ss == standard deviation of the initialstandard deviation of the initialsamplesample

xx == mean of the initial samplemean of the initial sample

nn == required sample sizerequired sample size



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Required sample size = n =Required sample size = n =

22zszs

hxhxDesiredConfidence

(%)

z Value(standard deviation required for

desired level of confidence)

90.0 1.65

95.0 1.96

95.45 2.00

99.0 2.58

99.73 3.00

Common z Values



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Desired accuracy with 5%Desired accuracy with 5%Confidence level = 95%Confidence level = 95%Sample standard deviation = 1.0Sample standard deviation = 1.0Sample mean = 3.00Sample mean = 3.00

n =n =

22zszs

hxhx

n = = 170.74 171n = = 170.74 171

221.96 x 1.01.96 x 1.0

.05 x 3.05 x 3

h = .05h = .05 x = 3.00x = 3.00 s = 1.0s = 1.0

z = 1.96z = 1.96


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n =n =

22zszs

ee

If desired accuracy h is expressed as an absolute amount,If desired accuracy h is expressed as an absolute amount,substitute e for hx, where e is the absolute amount ofsubstitute e for hx, where e is the absolute amount of

acceptable erroracceptable error

VariationsVariations

When the standard deviation s is not provided, it mustWhen the standard deviation s is not provided, it mustbe computedbe computed

s = =s = =(x(xii - x)- x)

22 (Each sample observation - x)(Each sample observation - x)22

n - 1n - 1 Number in sample - 1Number in sample - 1



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Work SamplingWork Sampling

Estimates percent of time a worker spendsEstimates percent of time a worker spendson various taskson various tasks

Requires random observations to recordRequires random observations to recordworker activityworker activity

Determines how employees allocate theirDetermines how employees allocate theirtimetime

Can be used to set staffing levels, reassignCan be used to set staffing levels, reassignduties, estimate costs, and set delayduties, estimate costs, and set delayallowancesallowances


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Advantages of work samplingAdvantages of work sampling

Less expensive than time studyLess expensive than time study

Observers need little trainingObservers need little training

Studies can be delayed or interrupted withStudies can be delayed or interrupted withlittle impact on resultslittle impact on results

Worker has littleWorker has littlechance to affectchance to affectresultsresults

Less intrusiveLess intrusive



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Disadvantages of work samplingDisadvantages of work sampling

Does not divide work elements as completelyDoes not divide work elements as completely

as time studyas time studyCan yield biased results if observer does notCan yield biased results if observer does not

follow random patternfollow random pattern

Less accurate, especially whenLess accurate, especially whenjob element times are shortjob element times are short



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1.1. Take a preliminary sample to obtainTake a preliminary sample to obtainestimates of parameter valuesestimates of parameter values

2.2. Compute the sample size requiredCompute the sample size required3.3. Prepare a schedule for random observationsPrepare a schedule for random observations

at appropriate timesat appropriate times

4.4. Observe and record worker activitiesObserve and record worker activities

5.5. Determine how workers spend their timeDetermine how workers spend their time



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Determining the sample sizeDetermining the sample size

n =n =

zz22 p(1 - p)p(1 - p)

hh22

wherewhere nn == required sample sizerequired sample size

zz == standard normal deviate forstandard normal deviate for

desired confidence leveldesired confidence levelpp == estimated value of sampleestimated value of sampleproportionproportion

hh == acceptable error level inacceptable error level in

percentpercent



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Work Sampling ExampleWork Sampling Example

Wants employees idle 25% of the timeWants employees idle 25% of the time

Sample should be accurate within 3%Sample should be accurate within 3%

Wants to have 95.45% confidence in the resultsWants to have 95.45% confidence in the results

n =n = zz22 p(1 - p)p(1 - p)

hh22

wherewhere nn == required sample sizerequired sample size

zz == 2 for a 95.45% confidence level2 for a 95.45% confidence level

pp == estimate of idle proportion =estimate of idle proportion =25% = .2525% = .25

hh == acceptable error of 3% = .03acceptable error of 3% = .03

n = = 833 observationsn = = 833 observations(2)(2)22 (.25)(.75)(.25)(.75)

(.03)(.03)22


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No. ofNo. ofObservationsObservations

ActivityActivity

485485 On the phone or meeting with a welfare clientOn the phone or meeting with a welfare client

126126 IdleIdle

6262 Personal timePersonal time

2323 Discussions with supervisorDiscussions with supervisor

137137 Filing, meeting, and computer data entryFiling, meeting, and computer data entry

833833

All but idle and personal time are work related.All but idle and personal time are work related.

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

Since this is less than the target value of 25%, theSince this is less than the target value of 25%, theworkload needs to be adjusted.workload needs to be adjusted.

Work Sampling ExampleWork Sampling Example


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Work Sampling Time StudiesWork Sampling Time Studies

SalespeopleSalespeople

TelephoneTelephonesalessales12%12%

TelephoneTelephonewithin firmwithin firm

13%13%

Lunch andLunch andpersonalpersonal

10%10%

MeetingsMeetingsand otherand other

8%8%

Paperwork17%

Travel20%

Sales inperson

20%


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Predetermined Time StandardsPredetermined Time Standards

Divide manual work into small basic elementsDivide manual work into small basic elementsthat have established timesthat have established times

Can be done in a laboratory away from theCan be done in a laboratory away from theactual production operationactual production operation

Can be set beforeCan be set beforethe work is actuallythe work is actually

performedperformed

No performanceNo performanceratings are necessaryratings are necessary


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MTM ExampleMTM Example

Weight - less than 2 poundsWeight - less than 2 pounds

Conditions of GET - easyConditions of GET - easy

Place accuracy - approximatePlace accuracy - approximate

Distance range - 8 to 20 inchesDistance range - 8 to 20 inches

Element DescriptionElement Description ElementElement TimeTime

Get tube from rackGet tube from rack AA2AA2 3535

Get stopper, place on counterGet stopper, place on counter AA2AA2 3535

Get centrifuge tube, place at sample tableGet centrifuge tube, place at sample table AD2AD2 4545

Pour (3 seconds)Pour (3 seconds) PTPT 8383Place tubes in rack (simo)Place tubes in rack (simo) PC2PC2 4040

Total TMUTotal TMU 238238

.0006 x 238 =.0006 x 238 = Total standard minutesTotal standard minutes = .14= .14


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MTM TableMTM Table

Work Measure

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