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Work Measurements
Lab # 5
Outline
1. Work Study
2. Method Study
3. Work Measurement
4. Time Study
3. Standard Time
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Work Study
• Work Study is a generic term for management services
and system engineering techniques, used to investigate:
– Methods of performing work (Method Study).
– The time taken to do it (Work Measurement).
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Work Study (Cont.)
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System Relationships
Process
analysis
Engineer workflows
Design work station &
information arrangements
Jobs
Method
study
Work
breakdowns
Plant
layout
Time
study
standard
times
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Lab # 5: Work Measurements
Incentive
rewards
5
Method Study
• Method study is a technique to reduce the work content
mainly by eliminating unnecessary movements by
workers, materials, or equipments.
• However, even after that, there could be substantial
unnecessary time taken for the process because of lack of
management control or inaction of worker.
• Method Study approaches and tools of Method Analyst:
– Flow Diagrams & Process Charts etc.
– Critical questioning techniques.
Will be covered in the next lab
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Work Measurement
• Work measurements (WM) are techniques used to
establish the time for a qualified, motivated worker to
carry out a task at a defined rate of working.
• Work measurement used to determine the standard
number of minutes taht aqualified properly trained, and
experienced person should take to perform a specific task
or operation when working at a normal pace.
• Work measurement is concerned with investigating,
reducing and eliminating ineffective time, whatever may
be the cause.
• In practice, proving existence of the ineffective time is the
most difficult task.
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Work Measurement (Cont.)
• WM is also used to set standard times to carry out the
work, so that any ineffective time is not included later.
• Any addition the standard time would show up as excess
time and thus can be brought to attention.
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Techniques for WM
• Two alternative method:
– Direct work measurement:
• Time study: “the most widely used”
• work sampling: Determines the proportion of time a
worker spends on activities
– Indirect work measurement (indirect method not on
the task) with standard times are measured by
standard data and formulation.
• Synthesis from standard data.
• Pre-determined motion time system.
• Estimating.
• Analytical estimating.
• Comparative estimating.
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Purpose of WM
• Work Measurement Purposes may be:
− To reveal the nature and extent of ineffective time, from
whatever cause.
− So that action can be taken to eliminate it; and then,
− To set standards of performance that are attainable only
if all avoidable ineffective time is eliminated and work is
performed by the best method available
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Applications of WM
• To compare the efficiency of alternative methods. Other
conditions being equal, the method which takes the least
time will be the best method.
• To balance the work of members of teams, in association
with the multiple activity charts, so that, as far as possible,
each member has tasks taking an equal time.
• To determine, in association with man and machine
multiple activity charts, the number of machines a worker
can run.
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Uses of Time Standards
• To provide information on which the planning and
scheduling of production can be based, including the plant
and labor requirements for carrying out the program of
work and utilization of resources.
• To provide information on which estimates for tenders,
selling prices and delivery promises can be based.
• To set standards of machine utilization and labor
performance which can be used for incentive scheme.
• To provide information for labor-cost control and to
enable standard costs to be fixed and maintained.
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Time Study
• Time Study: is the development of a standard time by
observing a task and analyzing it with the use of a
stopwatch
• Time Study includes:
– Establishment of standard times - management knowledge
– Rating operator performance - criteria for appraisal
– Gathering information to calculate production capabilities & data
for capacity planning.
– Defining work content of finished goods and services e.g. for
charging & estimating.
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Time Study
Before Time Studies
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After Time Studies
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Overview of Time Study
1. Secure and record information about the
operation and operator being studied.
2. Orient the supervisor and the workers.
3. Improve the work methods.
4. Break the task into elements and record.
5. Observe and record the time taken by the
operator.
6. Determine the number of cycles to be timed.
7. Rate the operator’s performance.
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Overview (cont.)
8. Check to make certain that a sufficient number of
cycles have been recorded.
9. Determine the allowances.
10. Determine the time standard for the operation.
11. Check and debug the standards with audits.
12. Implement with recall review in one month.
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Reasons for Element Breakdown
• Data is more readily reusable when each element
is described separately, esp. beginning and ending
points.
• Standard (estimated) time values may be
determined.
• Individual elements may be excessively short (e.g.,
inspection), or too long. These can be picked out
more easily in element form.
• This allows for separate performance ratings for
each.
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Taking and Recording of Data
• Continuous timing - records readings at the end of each
element as watch runs
• Repetitive timing - after recording, watch is snapped back
to zero at the end of each element
• Multiple watches - connected by a lever; one runs,
another is stopped, another set to go
• Electronic watch - may continue in “split” mode
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Stopwatch Time Study Basic Steps
1.
2.
3.
4.
5.
Establish standard job method
Break down job into elements
Study job
Rate worker’s performance (RF)
Compute average time (t)
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Standard time
• Standard time:
The amount of time it should take a qualified worker to
complete a specific task, working at a sustainable rate,
using given methods, tools and equipment, raw materials,
and workplace arrangement.
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Standard Time (Cont.)
• Two basic approaches to defining standard time.
– Bottom-up
• Starts with a basic measurement of time, adjusts for
operator pace, and then allows for fatigue, personal
needs, and delays.
– Top-down
• used in many labor contracts, and it normally defines
standard time as that time under which a qualified
employee working under usual conditions can make
an incentive pay (specified) percent above base pay.
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Standard Time (Cont.)
• Normal Time.
– The time required for an average, trained operator to perform a
task under usual working conditions and working at a normal pace.
(It does not include allowances for personal needs and delays that
would be necessary if the task were done all 8 hours.)
• Normal Pace.
– The pace of an average, trained, and conscientious operator
working over an 8-hour day.
• Actual Time.
– The observed time required for an operator to perform a task.
• Allowances.
– The amount of time added to the normal time to provide for
personal needs, unavoidable delays, and fatigue.
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Doing Time Study
• When making a time study several decisions are made to
assure desired results:
– # of observations to make
– Desired level of accuracy
– Desired level of confidence for the estimated standard
time
• Desired accuracy level is typically expressed as a % of the
mean observed times.
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Doing Time Study
(cont.)
• The normal time (NT) is the mean observed time
multiplied by the Performance Rating Factor (PRF)
• The PRF is a subjective estimate of a worker’s pace relative
to a normal work pace.
• The Performance Rating is usually expressed in decimal
form in these formulas. So a person working 10% faster
than normal would have a Performance Rating of 1.10 or
110% of normal time. Working 10% slower, 0.90 or 90%
of normal.
• The frequency of occurrence (F) is how often the
element must be done each cycle.
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Doing Time Study
(cont.)
• The allowance factor (AF) is the amount of time
allowed for personal, fatigue, and unavoidable
delays.
•
Average observed time =
Sum of times recorded to perform each element / # of
observations
• NT = Average observed time x PRF x F
• ST = NT / (1 – AF) or NT ( 1+ AF)
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Allowances
• Personal time allowance - 4% - 7% of total time - use of
restroom, water fountain, etc.
• Delay allowance - based upon actual delays that occur
• Fatigue allowance - to compensate for physical or mental
strain, noise level, tediousness, heat and humidity,
assumption of an abnormal position, etc.
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Normal Time vs. Standard Time
Standard time is the total time in which a job should be
completed at standard performance.
Normal Time
Rest
Pers. Need
Delay
Standard Time
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Determining Labor Standards
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Example
Job Element
Cycle Observed (in minutes)
PRF
1
2
3
4
5
Compose and type letter
8
10
9
21*
11
90%
Type envelope address
2
3
2
1
3
85%
Stuff, stamp, and seal.
2
1
5*
2
1
94%
Allowance Factor =15%
Delete unusual or nonrecurring observations (marked with *)
21 in job A , 5 in Job C
• Compute average times for each element
Average time of job A = (8+10+9+11)/4 = 9.5 min.
Average time of job B= (2+3+2+1+3)/5 = 2.2 min.
Average time of job C= (2+1+2+1)/4 = 1.5 min.
•
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Example (cont.)
• Compute the normal time for each element
• NT = Average observed time x PRF x F
– NT of job A = 9.5 x 0.9 x 1 = 8.55min
– NT of job B = 2.2 x 0.85 x 1= 1.87 min
– NT of job C = 1.5 x 0.94 x 1 = 1.41 min
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

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Total Normal Time = 8.55+1.87+1.41 = 11.83 min
Standard Time = NT / (1 – AF) or NT ( 1+ AF)
ST = 11.83 /(1-0.15) =13.92 min
or ST =11.83 (1+0.15) = 13.6 min
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Questions
• Reconnecting the cables of the computer case.
• Compute the standard time of the process using 10%
allowance.
Work Element
Observation 1
Observation 2
Observation 3
Observation 4
Power cable
Mouse
Monitor
Keyboard
Speaker
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