Management Chapter 15 Homework You might begin class by asking the students if they have experienced service upsets and long waits due to poor capacity or staffing decision

35

47. In this chapter, we noted that the EDD rule minimizes the maximum job tardiness and

maximum lateness while the SPT rule minimizes the average flowtime. However, neither

of these rules minimize the average lateness or average tardiness. Use the Excel

Sequencing template to answer the following using the data below:

a. Try to find a sequence that minimizes the average lateness.

b. Try to find a sequence that minimizes the average tardiness.

c. Can you generalize your logic into a rule or procedure that will accomplish these

objectives most of the time?

This is an advanced problem for teams or advanced students.

For the sequence 1 to 8, the average lateness is 9.5 and tardiness is 11.25.

36

48. An attorney’s office operates with a single copier. At the beginning of a particular day the

following jobs are waiting for processing. All jobs must be distributed to clients or in court

by 9:00 a.m., and it is now 7:30 a.m.

Regular size paper takes an average of 1.0 second per page to complete, while the legal-

analysis.

First, compute the processing times for each job:

Job Job Content Processing Time

1 500 regular size paper 500(1) + 250(1.2) = 800 seconds

250 legal size papers

Since all due dates are the same, the EDD rule is not useful. The SPT sequence yields:

37

One job is late. Note however, that the total processing time (5580) exceeds the due date, so it is

impossible to complete all jobs on time.

Teaching Note: Luke’s Balloon Shop

Overview

A small business must sequence jobs using a single resource helium tank to fill balloons used in

parties, wedding, bachelor parties, etc. Processing and due date times are given and the

Case Questions for Discussion:

1. Compute the average flowtime, lateness, and tardiness for this group of jobs using Mr.

Sailboat’s sequential order of 1 (first), 2, 3, 4, 5, and 6 (last).

Job Flow time Due Dates Lateness Tardiness

—– ———— — —————– ————– ———–—

1 240 240 0 0

2 370 360 10 10

2. In what order would the jobs be processed using the SPT rule? Compute the average

flowtime, lateness, and tardiness for this group of jobs.

38

Job Flow time Due Dates Lateness Tardiness

— ———— — —————– ————– —-——–

4 90 240 -150 0

2 90+130=220 360 -140 0

3. Compare the answers in Questions 1 and 2.

SPT minimizes the average time a job spends in the shop either waiting or being processed

4. What are your short-term recommendations for this set of six jobs? Explain your reasoning.

Use SPT to sequence these jobs. Ms. Davis may want to bring in some part-time help to

5. What are your long-term recommendations with respect to sequencing jobs at Luke’s store?

Explain your reasoning.

They need to evaluate equipment capacity and determine “when” they need to install a

Teaching Note: Midwest Frequent Flyer Call Center

Overview

Students must follow the four-step process described in the case and use Equation 7.2 to

39

Case Questions for Discussion:

1. Analyze the case data and current schedule, and answer the following “baseline”

questions. What’s labor utilization for each 30-minute period given the current staffing

plan? Is the main problem lack of staff capacity or poor scheduling, or both? Can you

support your answer with numerical analysis?

See TN Exhibits A, B &C to answer issues in case question (1). From Exhibit B we see that

current CSR utilization ranges for 38% to 160% with high variability—this is evidence of a

2. What is the cost of abandoned and busy signal calls for a typical Monday? Annually?

(Make and state assumptions as needed).

Given the data in the case, 5.4% (103/1,897) of total calls are abandoned and 2.6%

(50/1,897) of customers receive a busy signal and hang up for this example one day.

3. Develop a better CSR staff schedule (see Excel posted current staff schedule) if needed

and decide whether they should hire more CSRs or layoff a few. Will you use part-time

employees? If so, explain why and justify your reasoning.

See the TN Staff schedule discussion and schedules.

40

TN Exhibit B CSR Demand – Capacity Analysis

Time

Period

Number

of

Number

of

Number

of

Total

Calls

Current

Equation

7.2

Equation 7.2

Rounded

Calls

Taken

Abandon

Busy

Signal

Number

of

Current

Target

to Next

Calls by

Calls

CSRs

CSR

Number of

Highest

Customer

Not Taken

On-Duty

Utils (%)

CSRs@90% +

Number

6:30

15

0

15

2

0.60

1.3

2.0

7:00

16

0

16

2

0.64

1.4

2.0

7:30

45

4

0

49

3

1.31

4.4

5.0

8:00

60

5

0

65

5

1.04

5.8

6.0

8:30

62

6

2

70

5

1.12

6.2

7.0

9:00

71

4

1

76

5

1.22

6.8

7.0

9:30

77

5

0

82

5

1.31

7.3

8.0

10:00

84

4

99

6

1.32

8.8

9.0

10:30

75

8

3

86

7

0.98

7.6

8.0

11:00

81

4

3

88

7

1.01

7.8

8.0

12:00

79

2

0

81

6

1.08

7.2

8.0

12:30

66

3

2

71

6

0.95

6.3

7.0

1:00

80

4

3

87

5

1.39

7.7

8.0

1:30

76

8

6

90

4.5

1.60

8.0

2:00

92

6

7

6

1.40

9.3

10.0

2:30

85

7

5

97

0.74

8.6

9.0

41

4:00

67

4

75

7

0.86

6.7

7.0

4:30

62

2

0

64

7

0.73

5.7

6.0

5:00

54

1

0

55

4.5

0.98

4.9

5.0

5:30

51

1

53

5

0.85

4.7

5.0

6:00

37

0

37

5

0.59

3.3

4.0

6:30

48

3

2

53

4

1.06

4.7

5.0

7:00

42

0

42

4

0.84

3.7

4.0

8:00

26

2

0

28

4

0.56

2.5

3.0

8:30

22

1

0

23

4

0.46

2.0

3.0

9:00

19

0

19

4

0.38

1.7

2.0

Totals

1744

103

50

1897

163.5

28.10

168.51

182.00

Average

58.1

3.4

1.7

63.2

5.5

0.94

5.62

6.07

22.9

2.8

2.0

26.6

2.2

0.31

2.36

2.33

19

0

19

4

0.38

1.69

2.00

Maximum

92

7

105

1.60

9.33

10.00

Note (+): Standard time of 12.51 calls/CSR/30 minutes. We rounded here to integers but some students will

round to one-half FTEs since with breaks you can have say 1.5 or 4.5 FTEs per 30-minute time period. .

42

CURRENT and BLANK STAFF SCHEDULE WORKSHEETS (6:30 am to 2:00 pm)

CURRENT and BLANK STAFF SCHEDULE WORKSHEETS (2:30 PM TO 9:00 PM)

The current staff schedule is 13 employees with 9 full time (FTE greater than 7 hours plus 1

hour lunch + at least one 15-minute break) and 4 part-time (defined as anything other than full-

time). Using part time employees reduces total labor costs including benefits (i.e., the

Exhibit 13.20 Greyhound

CSR Staff Schedule for Horizon Airlines

Service Rep 6:30 7:00 7:30 8:00 8:30 9:00 9:30 10:00 10:30 11:00 11:30 12:00 ####### 1:00 1:30 2:00

1X————

—————

—————–

(—-)——-

—————

(Lunch) (Lunch)

—————

—–(—-)

—————

———–

2X————

—————

—————–

—–(—-)

—————

(Lunch) (Lunch)

—————

(—-)——-

———–

3X————

—————

—————–

—————

(—-)——-

—————

(Lunch) (Lunch)

—————

(—-)——-

—————

4X————

—————–

—————

—–(—-)

—————

(Lunch) (Lunch)

—————

—–(—-)

—————

5X————

—————–

—————

(—-)——-

—————

(Lunch) (Lunch)

—————

(—-)—–

6X————

—————

—–(—-)

—————

(Lunch) (Lunch)

—————

—–(—-)

Exhibit 3 Current

CSR Staff Schedule for Horizon Airlines (continued)

Service Rep 2:30 3:00 3:30 4:00 4:30 5:00 5:30 6:00 6:30 7:00 7:30 8:00 8:30 9:00 Totals

1

2

3———– ———–

4

—————

———– ———–

5

—————

———–

6

—————

———–

—————

(—-)——-

—————

(—-)——-

Short/Excess (-/+)

—————

(—-)——-

—————

43

4. What are your final recommendations?

Students will make a wide variety of recommendations. Typical staffing plans depending on

assumptions range from (a) fifty percent full-time and fifty percent part-time employees to

meet call center demand, (b) 100% full time, and (c) some mix such as 75% full time and 25%

part-time. As long as their logic, presentations, clarity, and so on are sound we normally give

You will find student charts of demand and capacity to be very well done and colorful.

Teaching Approach

You might begin class by asking the students if they have experienced service upsets and long

waits due to poor capacity or staffing decisions. Let them tell their stories and then ask them

“Any idea if the root cause was a capacity or scheduling problem or both? Also, Exhibit 13.2

45

46

Integrative Case: Hudson Jewelers

Chapter 15 Case Questions for Discussion:

1. Develop a staff schedule between the hours of 9 a.m. and 8 p.m. for week 8, which had

587 visits (see the worksheet Hudson Jeweler Demand Case Data in MindTap). Assume

the maximum service rate is ten customers per hour per store employee. You will have to

allocate the demand over the day and time periods. You may use the Excel Hudson

Jeweler Staffing Schedule Worksheet that is available in MindTap or create your own.

Note: Please note that for service businesses such as Hudson Jewelers, Exhibit 14.2 applies, and

therefore, intermediate (Level 2) planning is not necessary for service businesses. That is,

aggregate plans are immediately disaggregated to detailed frontline resource (capacity)

planning and scheduling decisions.

• Peak demand in Hudson Jeweler Demand Case Data worksheet occurs in week 8 at 587

customer visits per week.

• The store is open 10 am to 5 pm Monday, Wednesday, Thursday, and Saturday or 7

Next is a typical student staff schedule and answer.

47

We think that hiring an extra person from 4-8 p.m. would free up Jasime to work one-on-one

with customer appointments and CAD.

2. What are the advantages and disadvantages of your store-staffing schedule?

Advantages

Disadvantages

• Just enough Employees to help Customers

3. Would you hire non-family employees to staff this single store? Explain your reasoning.

No, because customers see the store as a family owned and operated, customers would lose on

Staffing 9:00 9:30 10:00 10:30 11:00 11:30 12:00 12:30 1:00 1:30 2:00 2:30 3:00

Bill Hudson Start

—————

(Lunch Lunch) ———————–

Jasime Navey Start

————

—————

(Lunch Lunch)

Betty Hudson Start

—————

——————————–

Thomas Navey

Possible Staff A

537 customer visits for week 8

537/48 total hours that week = 5.6 customers per 1/2 hour

Staffing 3:30 4:00 4:30 5:00 5:30 6:00 6:30 7:00 7:30 8:00 Totals

Bill Hudson

—————

End

Jasime Navey

—————

End

———————————————————————————–