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Lecture 14
Job Design and Work Measurement
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© 2006 Prentice Hall, Inc.
Learning Objectives When you complete this chapter, you should be able to: 1. Describe labor planning policies 2. Identify the major issues in job design 3. Identify major ergonomic and work environment issues 4. Use the tools of methods analysis 5. Understand the contribution of the visual workplace 2
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Learning Objectives When you complete this chapter, you should be able to: 4. Identify four ways of establishing labor standards 5. Compute the normal and standard times in a time study 6. Find the proper sample size for a time study
Learning Objectives When you complete this chapter, you should be able to: 7. Explain how predetermined time standards and TMUs are used in work measurement 8. Apply the five steps of work sampling
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Human Resource Strategy The objective of a human resource strategy is to manage labor and design jobs so people are effectively and efficiently utilized 1. People should be effectively utilized within the constraints of other operations management decisions 2. People should have a reasonable quality of work life in an atmosphere of mutual commitment and trust 5
Constraints on Human Resource Strategy Product strategy • • • •
Process strategy
Skills needed Talents needed Materials used Safety
• Technology • Machinery and equipment used • Safety
Schedules
• Time of day • Time of year (seasonal) • Stability of schedule
When
HUMAN RESOURCE STRATEGY
Individual differences Who • Strength and fatigue • Information processing and response
Location strategy
Layout strategy
• • • • •
• • • • •
Climate Temperature Noise Light Air quality
Fixed position Process Assembly line Work cell Product
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Labor Planning Employment Stability Policies 1. Follow demand exactly Matches direct labor costs to production Incurs costs in hiring and termination, unemployment insurance, and premium wages
Labor is treated as a variable cost 7
Labor Planning Employment Stability Policies 2. Hold employment constant Maintains trained workforce Minimizes hiring, termination, and unemployment costs Employees may be underutilized during slack periods Labor is treated as a fixed cost 8
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Work Schedules Standard work schedule Five eighteight-hour days
Flex Flex--time Allows employees, within limits, to determine their own schedules
Flexible work week Fewer but longer days
Part Part--time Fewer, possibly irregular, hours 9
Job Classification and Work Rules Specify who can do what Specify when they can do it Specify under what conditions they can do it Often result of union pressure Restricts flexibility in assignments and consequently efficiency of production 10
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Job Design Specifying the tasks that constitute a job for an individual or a group 1. Job specialization 2. Job expansion 3. Psychological components 4. Self Self--directed teams 5. Motivation and incentive systems 11
Labor Specialization The division of labor into unique tasks First suggested by Adam Smith in 1776 1. Development of dexterity and faster learning 2. Less loss of time 3. Development of specialized tools
Later Charles Babbage (1832) added another consideration
4. Wages exactly fit the required skill 12
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Job Expansion Adding more variety to jobs Intended to reduce boredom
associated with labor specialization Job enlargement Job rotation Job enrichment Employee empowerment 13
Job Enlargement and Job Enrichment Enriched job
Planning (participating in a crossfunction qualityimprovement team)
Enlarged job Task #3
(lock printed circuit board into fixture for next operation)
Present job
(manually insert and solder six resistors)
Task #2 (adhere labels to printed circuit board)
Control
(Test circuits after assembly)
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Psychological Components of Job Design Human resource strategy requires consideration of the psychological components of job design
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Hawthorne Studies They studied light levels, but discovered productivity improvement was independent from lighting levels
Introduced psychology into the workplace The workplace social system and distinct roles played by individuals may be more important than physical factors
Individual differences may be dominant in job expectation and contribution
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Core Job Characteristics Jobs should include the following characteristics
Skill variety Job identity Job significance Autonomy Feedback 17
Self--Directed Teams Self Group of empowered individuals
working together to reach a common goal May be organized for longlong-term or short--term objectives short Effective because Provide employee empowerment Ensure core job characteristics Meet individual psychological needs 18
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Job Design Continuum Self-directed teams Empowerment Enrichment Enlargement Specialization
Increasing reliance on employee’s contribution and increasing responsibility accepted by employee
Job expansion 19
Self--Directed Teams Self To maximize effectiveness, managers should
Ensure those who have legitimate contributions are on the team
Provide management support Ensure the necessary training Endorse clear objectives and goals Financial and nonnon-financial rewards Many teams have definite life cycles 20
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Benefits of Teams and Expanded Job Designs
Improved quality of work life Improved job satisfaction Increased motivation Allows employees to accept more responsibility
Improved productivity and quality Reduced turnover and absenteeism 21
Limitations of Job Expansion 1. Higher capital cost 2. Individuals may prefer simple jobs 3. Higher wages rates for greater skills 4. Smaller labor pool 5. Higher training costs
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Motivation and Incentive Systems Bonuses - cash or stock options Profit Profit--sharing - profits for distribution to employees
Gain sharing - rewards for improvements Incentive plans - typically based on production rates
Knowledge Knowledge--based systems - reward for knowledge or skills
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Maslow’s Hierarchy of Needs Self-Actualization SelfUse of abilities Self-fulfillment
Ego Self Respect Social Group Interaction Job Status Safety Physical Safety Job Security Physiology Food Shelter
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Understanding of employees’ need level will help managers motivate them work with higher productivity 25
Ergonomics and the Work Environment Ergonomics is the study of the interface between man and machine Often called human factors Operator input to machines
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Ergonomics and Work Methods Feedback to operators The work environment Illumination Noise Temperature Humidity
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Levels of Illumination Task Condition
Type of Task or Area
Small detail, extreme accuracy
Sewing, inspecting dark materials
Normal detail, prolonged periods
Reading, parts assembly, general office work
Good contrast, fairly large objects Large objects
Illumination Level
Type of Illumination
100
Overhead ceiling lights and desk lamp
20-50
Overhead ceiling lights
Recreational facilities
5-10
Overhead ceiling lights
Restaurants, stairways, warehouses
2-5
Overhead ceiling lights 28
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Decibel Levels Environment Noises
Common Noise Sources
Decibels
Jet takeoff (200 ft) Electric furnace area
Pneumatic hammer
Printing press plant
Subway train (20 ft) Pneumatic drill (50 ft)
Inside sports car (50 mph) Near freeway
Vacuum cleaner (10 ft) Speech (1 ft)
Private business office Light traffic (100 ft)
Large transformer (200 ft)
Minimum levels, Chicago residential areas at night Studio (speech)
Soft whisper (5 ft)
120 | 100 | 90 | 80 | 70 | 60 | 50 | 40 | 30
Very annoying
Ear protection required if exposed for 8 or more hours Intrusive Quiet
Very quiet 29
Methods Analysis Focuses on how task is performed Used to analyze 1. Movement of individuals or material Flow diagrams
2. Activities of human and machine and crew activity Activity charts/ man man--machine charts
3. Body movement Micro Micro--motion charts 30
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Flow Diagram Welding From Storage bins
press mach.
Mach. 3
Mach. 4
Paint shop
Machine 1
Mach. 2
Old Method
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Flow Diagram
Machine 4
Welding
Machine 3 Paint shop
Machine 2 Machine 1 From press mach.
New Method
Storage bins
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Process Chart
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Activity Chart
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Operation Chart
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The Visual Workplace Use lowlow-cost visual devices to share information quickly and accurately
Displays and graphs replace printouts and paperwork
Able to provide timely information in a dynamic environment
System should focus on improvement 36
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The Visual Workplace Visual signals can take many forms and serve many functions
Present the big picture Performance Housekeeping
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The Visual Workplace Visual utensil holder encourages housekeeping
A “3“3-minute service” clock reminds employees of the goal
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The Visual Workplace Visual signals at the machine notify support personnel
Visual kanbans reduce inventory and foster JIT Reorder point
Line/machine stoppage Parts/ maintenance needed All systems go Part A
Part B
Part C
Andon 39
The Visual Workplace
Quantities in bins indicate ongoing daily requirements and clipboards provide information on schedule changes
Process specifications and operating procedures are posted in each work area 40
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Ethics and the Work Environment Fairness, equity, and ethics are
important constraints of job design
Important issues may relate to equal opportunity, equal pay for equal work, and safe working conditions
Helpful to work with government
agencies, trade unions, insurers, and employees 41
Labor Standards Effective manpower planning is
dependent on a knowledge of the labor required
Labor standards are the amount of time required to perform a job or part of a job
Accurate labor standards help
determine labor requirements, costs, and fair work 42
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Labor Standards and Work Measurement Started early in the 20th century Important to both manufacturing and service organizations
Necessary for determining staffing requirements
Important to labor incentive systems
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Meaningful Standards Help Determine 1. 2. 3. 4. 5. 6. 7.
Labor content of items produced Staffing needs Cost and time estimates Crew size and work balance Expected production Basis of wage incentive plans Efficiency of employees 44
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Labor Standards May be set in four ways: 1. Historical experience 2. Time studies 3. Predetermined time standards 4. Work sampling 45
Historical Experience How the task was performed last time Easy and inexpensive Data available from production records or time cards
Data is not objective and may be inaccurate
Not recommended 46
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Time Studies Involves timing a sample of a
worker’s performance and using it to set a standard
Requires trained and experienced observers
Cannot be set before the work is performed
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Time Studies – 8 steps 1. Define the task 2. Divide the task into precise elements 3. Decide how many times to measure the task 4. Time and record element times and rating of performance 48
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Time Studies - 8 steps 5. Compute average cycle time Average observed cycle time
=
sum of the times recorded to perform each element number of cycles observed
6. Determine performance rating and normal time (NT) average performance observed NT = x rating factor cycle time
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Time Studies - 8 steps 7. Add all the normal times for each element to develop the total normal time for the task 8. Compute the standard time (ST) ST =
total normal time 1 - allowance factor
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Rest Allowances Personal time allowance 4% - 7% of total time for use of restroom, water fountain, etc.
Delay allowance Based upon actual delays that occur
Fatigue allowance Based on our knowledge of human energy expenditure
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Rest Allowances (%) 1.
2.
Constant allowance (A) Personal allowance ……………... 5 (B) Basic fatigue allowance ………… 4 Variable allowances: (A) Standing allowance ……………… 2 (B) Abnormal position (i) Awkward (bending) ………… 2 (ii) Very awkward (lying, stretching) …………………… 7 (C) Use of force or muscular energy in lifting, pulling, pushing Weight lifted (pounds) 20 …………………………………… 3 40……………………………………. 9 60……………………………………. 17 (D) Bad light: (i) Well below recommended…. 2 (ii) Quite inadequate……………. 5
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Rest Allowances (%) (E) (F)
(G)
(H)
(I)
Atmospheric conditions (heat and humidity) …………… Close attention: (i) Fine or exacting……………….. (ii) Very fine or very exacting…… Noise level: (i) Intermittent— Intermittent—loud…………….. (ii) Intermittent— Intermittent—very loud or highhigh-pitched………………... Mental strain: (i) Complex or wide span of attention.…………………….. (ii) Very complex………………….. Tediousness: (i) Tedious…………..……………… (ii) Very tedious.……………………
0-10 2 5 2 5
4 8 2 5 53
Time Study Example 1 Average observed time = 4.0 minutes Worker rating = 85% Allowance factor = 13% NT = (average observed time) x (rating factor) = (4.0)(.85) = 3.4 minutes ST =
normal time 1 - allowance factor
3.4 3.4 = 1 - .13 = .87
= 3.9 minutes 54
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Time Study Example 2 Allowance factor = 15% Cycle Observed (in minutes) Job Element
1
2
3
(A) Compose and type letter
8
10
(B) Type envelope address
2
3
(C) Stuff, stamp, seal, and sort envelopes
2
1
5*
Performance Rating
4
5
9
21*
11
120%
2
1
3
105%
2
1
110%
1. Delete unusual or nonrecurring observations (marked with *) 2. Compute average cycle times for each element Average time for A = (8 + 10 + 9 + 11)/4 = 9.5 minutes Average time for B = (2 + 3 + 2 + 1 + 3)/5 = 2.2 minutes Average time for C = (2 + 1 + 2 + 1)/4 = 1.5 minutes 55
Time Study Example S2 3. Compute the normal time for each element NT = (average observed time) x (rating) NT for A = (9.5)(1.2) = 11.4 minutes NT for B = (2.2)(1.05) = 2.31 minutes NT for C = (1.5)(1.10) = 1.65 minutes
4. Add the normal times to find the total normal time Total NT = 11.40 + 2.31 + 1.65 = 15.36 minutes
5. Compute the standard time for the job ST = =
total normal time 1 - allowance factor 15.36 1 - .15
= 18.07 minutes 56
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Determine Sample Size How accurate we want to be The desired level of confidence How much variation exists within the job elements
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Determine Sample Size zs Required sample size = n = hx where
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h = accuracy level desired in percent of the job element expressed as a decimal 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 n = required sample size 58
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Determine Sample Size zs Common z Values Required sample size =n= hx
where
2
z Value (standard deviation required for level desired level of confidence) accuracy desired in percent of the
Desired Confidence (%)
h =
90.0job
element expressed 1.65as a decimal z 95.0 = number of standard1.96 deviations required for the desired level of confidence 2.00 s 95.45 = standard deviation of the initial sample 99.0 2.58 x = mean of the initial sample n 99.73 = required sample size3.00 59
Time Study Example 3 Desired accuracy with 5% Confidence level = 95% Sample standard deviation = 1.0 Sample mean = 3.00 h = .05 x = 3.00 s = 1.0 z = 1.96 (from Table S10.1 or Appendix I) zs n= hx
2
1.96 x 1.0 n= .05 x 3
2
= 170.74 ≈ 171 60
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New Tools
With PDA software, you can study elements, time, performance rate, and statistical confidence intervals can be created, edited, managed, and logged
Reduces or eliminates the need for data entry 61
Predetermined Time Standards
Divide manual work into small basic elements that have established times
Can be done in a laboratory away from the actual production operation
Can be set before the work is actually performed
No performance ratings are necessary
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MTM Table
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MTM Example Weight - less than 2 pounds Conditions of GET - easy Place accuracy - approximate Distance range - 8 to 20 inches Element Description
Element
Time
Get tube from rack
AA2
35
Get stopper, place on counter
AA2
35
Get centrifuge tube, place at sample table
AD2
45
PT
83
PC2
40
Pour (3 seconds) Place tubes in rack
Total TMU
238
.0006 x 238 = Total standard mins = .14 64
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Work Sampling Estimates percent of time a worker spends on various tasks Requires random observations to record worker activity Determines how employees allocate their time Can be used to set staffing levels, reassign duties, estimate costs, and set delay allowances 65
Work Sampling Advantages of work sampling Less expensive than time study Observers need little training Studies can be delayed or interrupted with little impact on results Worker has little chance to affect results Less intrusive 66
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Work Sampling Disadvantages of work sampling Does not divide work elements as completely as time study Can yield biased results if observer does not follow random pattern Less accurate, especially when job element times are short 67
Work Sampling procedure 1. Take a preliminary sample to obtain estimates of parameter values 2. Compute the sample size required 3. Prepare a schedule for random observations at appropriate times 4. Observe and record worker activities 5. Determine how workers spend their time 68
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Work Sampling Determining the sample size z2 p(1 - p) n= h2 where
n = required sample size z = standard normal deviate for desired confidence level p = estimated value of sample proportion h = acceptable error level in percent 69
Work Sampling example Estimate employees idle 25% of the time Sample should be accurate within 3% Wants to have 95.45% confidence in the results z2 p(1 - p) n= h2 where
n z p h
= = = =
required sample size 2 for a 95.45% confidence level estimate of idle proportion = 25% = .25 acceptable error of 3% = .03
(2)2 (.25)(.75) n= = 833 observations (.03)2 70
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Work Sampling No. of Observations
Activity
485
On the phone or meeting with a welfare client
126
Idle
62
Personal time
23
Discussions with supervisor
137
Filing, meeting, and computer data entry
833 All but idle and personal time are work related. Percentage idle time = (126 + 62)/833 = 22.6%. Since this is less than the target value of 25%, the workload needs to be adjusted. 71
Work Sampling Time Studies Salespeople
Telephone sales 12%
Telephone within firm 13%
Sales in Travel person 20% 20% Paperwork 17% Lunch and personal 10% Meetings and other 8% 72
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Work Sampling Time Studies Startup/pep talk 3%
Assembly-Line AssemblyEmployees
Breaks and lunch 10% Dead time between tasks 13% Productive work 67%
Unscheduled tasks and downtime 4% Cleanup 3%
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