Work Measurement
Vital inputs for:
•
•
•
•
•
Manpower and machine planning
Reducing labour costs
Scheduling
Budgeting
Designing incentive systems
Standard Time
Amount of time a qualified worker should spend to complete a
specified task, working at sustainable rate, using given methods,
tools and equipment, raw material and workplace
Most commonly used methods of work measurement:
•
•
•
•
Time study
Historical times
Predetermined data
Work sampling
Work Measurement
Time Study
• Most widely used method of work measurement
• Especially appropriate for short, repetitive tasks
Average of a few properly trained workers’
performed time are taken as the standard
Basic steps:
• Define the task to be studied, and inform the worker(s) who will be studied
• Determine the number of workers and cycles to be observed
• Time the job and rate the performance
• Compute the standard time
Work Measurement
Standard Elemental Time (SET)
derived from a firm’s own historical time study data
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•
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A time study department accumulates a file of elemental times that
are common to many jobs
After a certain point, many elemental times can be retrieved from the
file
Eliminate need for analysts to go through a complete time study to
obtain those
Predetermined Time Standards (PDTS)
published data on standard elemental times
• Commonly used system is Method-Time Measurement (MTM)
• MTM tables are based on extensive research of basic elemental times
Work Measurement
Work Sampling
technique for estimating the proportion of working time and idle time
Office time: 9 am to 5 pm
Working time = 6 hrs
Idle time = 2 hrs
Ratio = 6:2 = 3:1
appropriate for long, non-repetitive tasks
Two primary uses:
• Ratio-delay studies: concern the percentage of worker’s time
that involves delay
• Analysis of non-repetitive jobs: percentage of time an employee
spends doing various jobs
Work Measurement
Work Sampling
Ratio = 6:2 = 3:1
1~3
11 ~ 1
9 ~ 11
1~3
11 ~ 1
9 ~ 11
3~4
1~2
11 ~ 12
2 hrs
2 hrs
1 hr
2 hrs
3~5
1~3
11 ~ 1
1 hr
9 ~ 11
11 ~ 1
1~3
A
2
B
1
Work Measurement
Worker
min/pc (average)
A
8
B
9
C
10
D
11
E
12
x

OT =
i
n
= 10 min
Observed Time (OT): simply the average of the recorded times
Work Measurement
Normal Time (NT): observed time adjusted for worker performance
NT = OT * PR
Performance Rating
= 10 * 1.1 = 11 min
1.1
Standard Time (ST): normal time required for a job plus
an allowance time for different delays
ST = NT + NT * A = NT * (1 + A)
=11* (1 + 0.2) = 13.2 min
1 + A = AF
Allowance Factor
ST = NT * AF
Allowance
20%
Work Measurement
Worker
pcs/hr (average)
A
4
B
5
C
6
D
7
E
8
OT = 10 min
x

OT =
n
For job time
i
NT = OT * PR
AFjob =1 + A
ST = NT * AF
For time worked
AFtime =
1
1− A
Work Measurement
Worker
min/pc (average)
pcs/hr (average)
A
8
7.5
B
9
C
10
6.7
6
D
11
5.45
E
12
5
Worker
min/pc (average)
pcs/hr (average)
A
8
7
B
9
6
C
10
6
D
11
5
E
12
5
AFjob = 1 + A
AFtime =
1
1− A
Work Measurement
OT
ST = NT + NT * A
NT < ST
NT = OT * PR
For Good Worker, PR > 1
OT < NT < ST ST > OT
For Average Worker, PR = 1
OT = NT < ST ST > OT
For Bad Worker, PR < 1
OT > NT < ST ST
PR
AF
7 >5< 8
8 >5< 7
6 >5< 6
OT
Work Measurement
NT = OT * PR
OT = 10 min
ST = NT * AF
OT = 10 min
PR = 0.8
NT = 8 min
PR = 0.9
NT = 9 min
A = 0.2
ST = 9.6 min
A = 0.2
ST = 10.8 min
OT = 10 min
OT = 10 min
PR = 0.9
NT = 9 min
PR = 0.9
NT = 9 min
A = 0 .1
ST = 9.9 min
A = 0.2
ST = 10.8 min