1. Chapter 11
Work System Design

2. What to Design? Job design Work Measurement design
Worker Compensation design

3. Job Design Job design is to specify the contents of a job or position.
Examples of questions to be answered in job design:
What is the job’s description?
What is the purpose of the job?
Where is the job done?
Who does the job?
What background, training, or skills are required to do the job?

4. Feasibility Considerations of a Job
Technical feasibility
The job must be physically and mentally doable.
Economic feasibility
The cost of the job should be less than the value it adds.
Behavioral feasibility
How much satisfaction an employee feels from doing the job.
Technical feasibility: - Technical difficulty is related to size of applicant pool.
Economic feasibility: Example – Purchase half-processed vegetable vs. have labors to pick, wash, cut, mix vegetable.
Behavioral feasibility: - To make work a fun, as in the case of Google on page 413.

5. Case of Google, p
How jobs and job environment are designed

6. Machine or People? - Should Job Be Automated?
Considerations:
Safety & risk of injury to workers
Repetitive nature of the task
Degree of precision required
Complexity of the task
Need for empathy, compassion, or other emotional elements
Need for personal customer relationships

7. Labor Specialization What is the breadth of a job.
The higher the level of specialization, the narrower is the employee’s scope of expertise required.
Although job satisfaction is associated with many specialized professional jobs, dissatisfaction is often associated with specialized non-professional jobs.

8. Specialized Non-Professional Jobs Management’s View
Advantages:
Readily available labor
Minimal training required
Reasonable wages costs
High productivity
Disadvantages:
High absenteeism
High turnover rates
High scrap rates
Grievances filed

9. Specialized Non-Professional Jobs Employee’s View
Advantages:
Minimal credentials required
Minimal responsibilities
Minimal mental effort needed
Reasonable wages
Disadvantages:
Boredom
Little growth opportunity
Little control over work
Little room for initiative
Little intrinsic satisfaction

10. Eliminating Employee Boredom Enhance Employee Motivation
Job enlargement
Horizontal expansion of the scope of the work assigned.
Job enrichment
Vertical expansion of the job through increased worker responsibility. Example:
Adding work planning or inspection to a routine assembly task
Job rotation
Shifting workers to different tasks to increase understanding of the total process and reduce fatigue.

11. Team Approaches Considered in Job Design
Problem-solving teams:
For workplace problems
Special-purpose task forces:
For highly-focused, short-term problem solving
Self-directed teams:
Integrated team approach for controlling portions of the process.

12. Alternative Workplace
Some jobs are not necessarily carried out at the centralized work sites, office buildings, or work shops.
Alternative workplaces are made possible by technologies like Internet, , cell phones, & video conferencing.

13. Method Analysis
Method analysis is for designing the details of how a job is done.
The output of a Method Analysis process is a standard operating procedure for doing the job.
Job design tells the positions needed in an operation process; while method analysis tells the details of standard procedures of how each job is done.

14. Key Steps in Method Analysis
Collecting information.
Chart the job operation by showing the steps involved.
Evaluate step by step to identify the unnecessary non-value-added activities.
Make suggestion on procedure of doing the job.

15. A Method Analysis Case at FEAT Company (p.420-421)
Job:
Solder wires to transformer.
Current layout of workstation:
Fig
Current procedure:
Process chart in Fig. 11-2
How to improve the procedure?

16. Work Environment Work environment is a part of job design.
Environment of a work place include:
temperature, humidity, ventilation, illumination, noise, color, decoration, supporting facilities, …

17. Work Measurement
Work measurement is to determine the time a job takes (rather than “how” to measure a job).
Standard time of a job is how long the job should take.

18. Uses of Standard Time
With the benchmark of standard times for jobs, the company can
Cost a product and price a product;
Evaluate workers’ performance;
Plan and schedule facilities and workers.

19. Methods of Setting Standard Times
Time study
Elemental time data
Predetermined time data
Work sampling

20. Time Study
Time study is to determine the standard time of a job by actually observing the operator.
The operator knows he is observed for setting the standard time.

21. Keys in Time Study
Break the job into small elements that are easy to observe.
Calculate number of observations required.
Time each element.
Summarize the results, considering relevant human factors.

22. How Many Observations?
Take a trial sample of observations (10 for example), find out its mean and standard deviation s.
Calculate minimum observations, n:
where
z= number of standard deviations for desired confidence, see Table 11-3 on p.425;
a = desired accuracy as % of mean time , 5% for example.

23. Performance Rating Factor (PRF)
PRF is an attempt to counterbalance any unusual patterns noted in the observed work pace, for example, deliberately working slowly or faster.
Average work pace: PRF=1.
Slower than average: PRF<1.
Faster than average: PRF>1.

24. Frequency of Occurrence (F)
It indicates how often a work element must be done in each work cycle (the process to finish a job).
If an element is done in every cycle, then F=1.
If an element is done once in every N cycles, then F=1/N.

25. PFD Factor
PFD factor shows the percent of efficiency decrease due to personal time, fatigue, or unavoidable delays when workers continue to work on a job for hours.
PFD=12%, for example, indicates an estimate that worker’s efficiency will decrease by 12% from the normal if continuing to work on the job for hours.

26. Allowance Factor (AF)
AF is the factor taking PFD (personal time, fatigue, and unavoidable delay) into account.
For setting standard work times, AF is calculated as:
Note: Discussions of AF in the textbook on p.427 are confusing. Ignore the concept of AFjob.

27. Steps for Setting Standard Times of an Element by Time Study (1)
Run about a few (10 for example) trial observations on the work time of the element. Calculate the average observed time of the element and standard deviation s.

28. Steps for Setting Standard Times of an Element by Time Study (2)
Determine number of observations required, n:
where
z= number of standard deviations for desired confidence, see Table 11-3 on p.425;
a = desired accuracy as % of mean time , 5% for example.

29. Steps for Setting Standard Times of an Element by Time Study (3)
Run more observations on the work time of the element so that number of total observations, including the initial trial 10, equals to n.
Based on the n observations, calculate the average time which is called mean observed time (MOT).

30. Steps for Setting Standard Times of an Element by Time Study (4)
Figure out “performance rating factor (PRF)” of the worker who was observed in the time study.
Figure out “frequency of occurrence (F)” of the element.
Calculate normal time NT:
NT = (MOT)(PRF)(F).

31. Steps for Setting Standard Times of an Element by Time Study (5)
Figure out the “factor for personal time, fatigue, and unavoidable delay (PFD)”.
Calculate “allowance factor AF”:
Note: Ignore the formula AF=1+PFDgiven in book.
Calculate “standard time ST” of the element:
ST = (NT)(AF).

32. Standard Time of a Job
After finding out the standard time of every element of a job, the standard time of the job is the sum of the standard times of all those elements.

33. Elemental Time Database
It is the database of standard times of job elements from previous time studies.
If a job contains some elements that are already stored in the database, then new time studies for those elements are not necessary.
Adjustment may be needed.

34. Predetermined Time Database
It is the published database of elemental times.
It is used for setting the job time without doing new time studies.
One TMU (time measurement unit) equals to minute or seconds.
Example: p.430

35. Work Sampling
Working sampling is technique for setting the proportion of time a worker spends on a particular activity.
Compared to time study, work sampling does not time the activity; instead, it makes a bunch of random observations to identify the percent of time the worker is doing the activity.

36. How Many Observations?
Take a trial sample of observations (30 for example), find out proportion p of doing the activity in this sample.
Calculate minimum observations, n:
where
z= number of standard deviations for desired confidence, see Table 11-3 on p.425;
e = desired accuracy as % of true proportion, 3% for example.

37. Steps of Doing Work Sampling
Run 30 trial observations.
p = (number of times doing the activity) / 30.
Calculate number of observations:
Run (n-30) more observations.
Calculate p based on n observations
p = (number of times doing the activity) / n.

38. To Know Time Spent on an Activity
Two ways to get the information about a worker’s time spent on an activity among some other activities:
Direct observation as in time study;
Random checking as in work sampling.
These are also two ways of evaluating work pace and efficiency in management.

39. Compensation Time-based system Output-based system
Group incentive plan
Profit sharing
Gain sharing (sharing the saved cost)
Individual incentive or group incentive?

40. Learning Curve Tx = T1 * Ln = T1 * Llog2x
where Tx=time required to do the job for the x-th time,
T1=time required to do the job for the first time,
L= learning curve rate, between 0 and 1,
n = number of times the repeating time is doubled to reach x.

41. n and x

42. Example
The first time a task took a worker 12 hours to complete. Suppose the learning curve rate is 85%. How long it would take that worker to do the same task for the 16th time.
The repeating time is doubled 4 times (2,4,8,16) to reach 16. So,
T16 = 12 * = 12*0.522 = 6.26 hrs
T1 = 12 * = 12.
T2 = 12 * 0.85log2 = 12 * = 10.2
T3 = 12 * 0.85log3 = 12 * = 12 * = T4 = 12 * 0.85log4 = 12 * = 12 * = 8.67.
T5 = 12 * 0.85log5 = 12 * = 12 * = .
T6 = 12 * 0.85log 6 = 12 * = 12 * = .
T7 = 12 * 0.85log7 = 12 * = 12 * = .
T8 = 12 * 0.85log8 = 12 * = 12 * = .
T9 = 12 * 0.85log9 = 12 * = 12 * = .

43. Ideas Contained in Learning Curve
It would take less and less time for a worker to do a job again and again.
The performance time would decrease by a certain rate after the number of times repeated doubles.

44. Learning Curve Coefficient Table
Table11-9, p.437, provides values learning curve coefficient, LCCx= Llog2x = Ln, so that Tx=T1* LCCx.
The first column are values of x.
Five learning curve rates, L’s, are in the table.
For each rate L, “unit time” column gives values of LCCx, “total time” column gives cumulative LCC values LCC1+LCC2+LCC3+...

45. Example p.436
Estimate the time to complete an order of 24 conveyor bucket systems. Suppose the first system is estimated to need 120 hours, and learning curve rate L=85%.
(1) Time to finish the 12th system?
(2) Time to finish the 24th system?
(3) Total hours needed for all the 24 systems?

46. Use of Learning Curve
Learning curve is important in planning labor and resource needed, scheduling, and estimating cost for internal production or negotiation with the contractor to do the production.

47. Sensitivity of L on the Result
The learning curve result is sensitive to value of rate L, as below, assuming T1=1.
Production amount
Total Production Cost
% Cost Increase
Learning curve rate 85%
Learning curve rate 87% 1
1.0
0.0 10
5.8
6.3
8.6
100 34
39.6
16.4
1,000
198
249.6
26.1
10,000
1153.8
1571.6
36.2
100,000
6724.7
9895.5
47.2

48. How to Determine Rate L?
From the historical records on the same or similar job.
Do experiments if possible.
Subjective estimate based on experience.
Since value of L affects the result of learning curve calculation significantly, be cautious. A pragmatic method is to give the range of rate L, instead of a single value.