1

Work Measurement

2

Outline LABOR STANDARDS AND WORK MEASUREMENT HISTORICAL EXPERIENCE TIME-STUDIES PREDETERMINED TIME STANDARDS WORK SAMPLING

3

Learning Objectives

When you complete this supplement, you should be able to :

Identify or Define: Four ways of establishing labor standards

Describe or Explain: Requirements for good labor standards Time study Predetermined time standards Work sampling

4

Costing labor content of products Planning staffing needs Estimating time and cost for bids Planning production (crew size and work

balance) Estimating expected production Basing wage-incentive plans Determining employee efficiency

Uses of Labor Standards

5

Historical experience Time studies Predetermined time

standards (MTM) Work sampling

© 1995 Corel Corp.

Sources of Labor Standards

6

Historical Experience

Relatively easy, convenient, and inexpensive Not objective, unknown accuracy

Not recommended

7

Labor standards are based on observing worker doing task Observe only a sample of work Use average time & pace to set standard

Disadvantages Requires a trained & experienced analyst Standard cannot be set before task is

performed

Time Studies

8

The Eight Steps to Conducting a Time Study

Define the task to be studied (after a methods analysis) Break down the task into precise elements Decide how many times each element of the task must be

measured Record the times and ratings of performance for the task

elements Compute the average observed cycle time (element times

adjusted for unusual influences)

9

6. Compute the normal time for each task element: Normal time = (Average actual cycle time)

x (Rating factor) Sum the normal times for each element to

develop a total normal time for the task Compute the standard time:

The Eight Steps to Conducting a Time Study - continued

Standard time = Total normal time1- Allowance factor

10

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.

11

Rest Allowances (%) for Various Classes of Work

1. Constant allowance(a) Personal allowance ……………...(b) Basic fatigue allowance …………

2.Variable allowances:(A) Standing allowance ……………..(B) Abnormal position

(I) Awkward (bending) ………….(ii) Very awkward (lying, stretching) ……………………..

(C) Use of force or muscular energy in lifting, pulling, pushingWeight lifted (pounds)20 …………………………………40………………………………….60………………………………….

5 4

2

2

7

3 917

12

Rest Allowances (%) for Various Classes of Work - Continue

(D) Bad light(i) Well below recommended …..(ii) Quite inadequate …………….

(E) Atmospheric conditions (heat and humidity)Variable …………………………..

(F) Close attention(i) Fine or exacting ………………(ii)Very fine or very exacting …...

(G) Noise level(i) Intermittent – loud ……………(ii) Intermittent – very loud or high-pitched

2 5

1-10

2 5

2 5

13

Rest Allowances (%) for Various Classes of Work - Continue

(H) Mental strain(i) Complex or wide span of attention

………………………(ii) Very complex …………….

(I) Tediousness(i) Tedious …………………….(ii) Very tedious ………………

4 4

2 5

14

Time Studies - Sample Size

xhzs

n ,size Sample

h = accuracy level desired as percent of job element, expressed as a decimal (5% = 0.05)

z = number of standard deviations required for the desired level of confidence

s = standard deviation of the initial sample

x = mean of the initial sample

1

2

n

xixs :Note

15

Considerations in Determining Sample Size

How accurate do you want to be? What level of confidence do you want your

measurements to have? How much variation exists within the job

elements?

16

Common z values

Desired ConfidenceLevel (%)

Z Value

90.11 1.65

95.00 1.96

95.45 2.00

99.11 2.58

99.73 3.0099.0

17

Allowance factor Nonwork timeTotal time

Average element time Element times

Number of cycles

Normal time Average element time * Perf. Rating

Standard timeTotal normal time

1 - Allowance factor

=

=

=

=

Time Study Equations

18

Labor standards are set from times in published tables (e.g., MTM Table)

Procedure Divide manual work into basic elements Look up basic element times in table; sum

Advantages Times established in laboratory setting Useful for planning tasks Widely accepted by unions

Predetermined Time Standards

19

Time TMU Hand inMotion

DistanceMoved (in)

A B C A B

3/4 or less 2.0 2.0 2.0 1.6 1.6

1 2.5 2.5 3.6 2.3 2.3

2 4.0 4.0 5.9 3.5 2.7

A Reach to object in fixed location. B Reach to object in variable locations.C Reach to object jumbled with others.

1 TMU = .0006 minutes

MTM Table for Reach Motion

20

Sample MTM Table for GET and PLACE Motions

21

MTM-HC Analysis: Pouring Tube Specimen

Element Description Element TimeGet tube from rack AA2 35Get stopper, place on counter

AA2 35

Get centrifuge tube, place at sample tube

AD2 45

Pour (3 sec.) PT 83Place tubes in rack (simo) PC2 400.0006*238=Total standard minutes = 0.14

Total TMU

238

22

Labor standard is set using output and % of time worker spends on tasks

Involves observing worker at random times over a long period

Advantages Less expensive than time studies Observer requires little training

Disadvantages Ineffective with short cycles

Work Sampling

23

Used for Ratio delay studies Setting labor standards Measuring worker performance

Work Sampling

24

The Five Step Work Sampling Procedure

1. Take a preliminary sample to obtain an estimate of the parameter value

2. Compute the sample size required3. Prepare a schedule for observing the worker at

appropriate times4. Observe and record worker activities; rate worker

performance5. Determine how workers spend their time (usually as a

percent)

25

Work Sampling - Sample Size

h

ppzn

p = estimated value of sample proportion (of time worker is observed busy or idle)

h = accuracy level desired in percent, expressed as a decimal

26

Normal Time =(Total Time) (% of time working) (Rating)

Number of units Produced

Standard Time = Normal Time

1 - Allowance

Work Sampling Equations

27

Work Sampling Time Studies