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    Work Measurement 3

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    Miguel Hernandez
    Work sampling is a technique for establishing time standards by taking many instantaneous observations of workers' activities at random times. It involves defining activities, designing a sampling plan, collecting data, and analyzing the results to determine the percentage of time spent on different activities. It is useful for setting standards on both direct and indirect labor jobs. Some advantages are that it is economical, flexible, and less tedious than traditional time studies. However, it does not provide as much detail as time studies and workers may change behaviors if they know they are being observed.

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    Work Measurement 3

    Uploaded by

    Miguel Hernandez
    217 views16 pages
    Work sampling is a technique for establishing time standards by taking many instantaneous observations of workers' activities at random times. It involves defining activities, designing a sampling plan, collecting data, and analyzing the results to determine the percentage of time spent on different activities. It is useful for setting standards on both direct and indirect labor jobs. Some advantages are that it is economical, flexible, and less tedious than traditional time studies. However, it does not provide as much detail as time studies and workers may change behaviors if they know they are being observed.

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    Work sampling is a technique for establishing time standards by taking many instantaneous observations of workers' activities at random times. It involves defining activities, designing a sampling plan, collecting data, and analyzing the results to determine the percentage of time spent on different activities. It is useful for setting standards on both direct and indirect labor jobs. Some advantages are that it is economical, flexible, and less tedious than traditional time studies. However, it does not provide as much detail as time studies and workers may change behaviors if they know they are being observed.

    Copyright:

    © All Rights Reserved
    Download as PPTX, PDF, TXT or read online from Scribd
    Download as pptx, pdf, or txt
    217 views16 pages

    Work Measurement 3

    Uploaded by

    Miguel Hernandez
    Work sampling is a technique for establishing time standards by taking many instantaneous observations of workers' activities at random times. It involves defining activities, designing a sampling plan, collecting data, and analyzing the results to determine the percentage of time spent on different activities. It is useful for setting standards on both direct and indirect labor jobs. Some advantages are that it is economical, flexible, and less tedious than traditional time studies. However, it does not provide as much detail as time studies and workers may change behaviors if they know they are being observed.

    Copyright:

    © All Rights Reserved
    Download as PPTX, PDF, TXT or read online from Scribd
    Download as pptx, pdf, or txt
    of 16

    Work Sampling

    Work Sampling
    Also known as: ratio delay study ,
    random observation method , snap-
    reading method , and observation
    ratio study .
    A technique of getting facts about utilization
    of machines and human beings through a large
    number of instantaneous observations taken at
    random time intervals. The ration of
    observations of a given activity to the total
    observations approximates the percentage of
    time that the process is in that state of activity.
    Work sampling can be very useful for
    establishing time standards on both direct and
    indirect labor jobs. The procedure for conducting
    work sampling study for determining standard
    time of a job can be described step-wise.
    Uses of Work Sampling
    1. Activity and Delay Sampling
    To measure the activities and delays of
    workers or machines
    2. Performance Sampling
    To measure working time and non-
    working time of a person on a manual task,
    and to establish a performance rating or
    level for the person during the working time.
    3. Work Measurement
    To establish time standard for an
    operation.
    Work Sampling Procedure
    1. Define the problem
    a) Describe the job for which the standard
    time is to be determined.
    b) Unambiguously state and discriminate
    between the two classes of activities of
    operator on the job.
    2. Design the sampling plan
    a) Estimate the number of observations to
    be made
    b) Decide the period of the study (e.g. days,
    weeks, etc.)
    c) Prepare detailed plan for taking the
    observations. (observation schedule,
    method of observing, and person to be
    observed)
    Work Sampling Procedure
    3. Contact the person concerned and
    take them In confidence regarding
    conduct of the study.
    4. Collect the data at the pre-decided
    random
    Advantages of Work Sampling
    with Time Study
    1. Economical
    a) Many operators or activities are difficult
    or uneconomical to measure by time
    study can readily be measured by work
    sampling..
    b) Two or more studies can be
    simultaneously made of several operators
    or machines by a single observer.
    Ordinarily a work study engineer can
    study only one operator at a time when
    continuous time study is made.
    c) It usually requires fewer man-hours to
    make a work sampling study than to
    make a continuous time study. The cost
    may also be about a third of the cost of a
    Advantages of Work Sampling
    with Time Study
    1. Economical
    d) No stopwatch or other time measuring
    device is needed for work sampling
    studies.
    e) It usually requires less time to calculate
    the results of work sampling study. Mark
    sensing cards may be used which can be
    fed directly to the computing machines to
    obtain the results just instantaneously.
    2. Flexible
    a) A work sampling study may be
    interrupted at any time without affecting
    the results.
    b) Operators are not closely watched for
    Advantages of Work Sampling
    with Time Study
    3. Operators like it
    a) Work sampling studies are preferred to
    continuous time study by the operators
    being studied. Some do not like to be
    observed continuously for long period of
    time..
    4. Observers like it
    a) Work sampling studies are less fatiguing
    and less tedious to make the part of time
    study engineer..
    Advantages of Work Sampling
    with Time Study
    5. Operators like it
    a) Work sampling is applicable to a wide
    variety of situations in manufacturing,
    distribution, service industries, or office
    situations.
    b) Work sampling is useful when determine
    the nature of the distribution of work
    activities within a gang operation.
    Disadvantages of Work
    Sampling with Time Study
    a) Work sampling is not economical for the
    study of a single operator or operation or
    machine. Likewise, uneconomical for
    studying operators or machines located
    over wide areas.
    b) Work sampling study does not provide
    elemental time data.
    c) The operator may change his work
    pattern when he sees the observer.
    d) No record is usually made of the method
    being used by the operator.
    e) Compared to time study, the statistical
    approach of work sampling study is
    difficult to understand by workers.
    Work Sampling Formula

    Sample size = 4p X (1 p) = 4 (1 p)
    ( Ep) Ep
    Normal Time = Obs Time X Perf. Rating X
    Perf. Index
    Output
    Standard Time = NT X ( 1 / 1- Allowance)
    Examples
    1) Working: 36 observations
    Idle: 4 observations
    Total: 40 observations
    Percentage of:
    Idle Time = 4/40 X 100 = 10%
    Working Time = 36/40 X 100 = 90%
    On an 8hr working day:
    480 X 0.10 = 48mins (the operator was idle)
    480 X 0.90 = 432mins (the operator was
    working)

    .
    Examples
    2) Observed Time: 2.50 hrs
    Output: 80 units
    Perf. rating: 80%
    Allowance: 1/8 of 8hr shift
    Solution:
    NT = OT X PR X PI = (150mins)(0.80)(1)
    Output 80

    = 1.50mins/unit

    ST = NT (1 / 1 All) = 1.50 (1 / 1 0.125)


    = 1.71mins/unit

    .
    Examples
    3) Observed Time: 8 hrs
    Output: 480 units
    Perf. index: 125%
    Allowance: 1/8 of 8hr shift
    Working Time: 360mins

    Solution:
    PR = WT/OT = 360/480 = 0.75 = 75%

    NT = OT X PR X PI = (480mins)(0.75)(1.25)
    Output 480

    = 0.93mins/unit

    ST = NT (1 / 1 All) = 0.93 (1 / 1 0.125)


    = 1.06mins/unit

    .
    Examples
    4) Total Time: 8 hrs
    Output: 400 units
    Allowance: 15%
    Idle Time: 18%
    Perf. Index: 120%

    Solution:
    WT = 100 18 = 82%

    NT = OT X PR X PI = (480mins)(0.82)(1.20)
    Output 400

    = 1.18mins/unit

    ST = NT (1 / 1 All) = 1.18 (1 / 1 0.85)


    = 1.39mins/unit
    .
    Thank You

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