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Wiley 2010 1

Chapter 13 AggregatePlanning

Operations Managementby

R. Dan Reid & Nada R. Sanders4th Edition Wiley 2010


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Wiley 2010 2

Learning Objectives Explain business planning

Explain sales and operations planning

Identify different aggregate planning strategies & optionsfor changing demand and/or capacity in aggregate plans

Develop aggregate plans, calculate associated costs, and

evaluate the plan in terms of operations, marketing,

finance, and human resources

Describe differences between aggregate plans for service

and manufacturing companies


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Wiley 2010 3

The Role of Aggregate

Planning Integral to part of the business planning

process

Supports the strategic planAlso known as the production plan

Identifies resources required for

operations for the next 6-18 months Details the aggregate production rate and

size of work force required


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The Role of the Aggregate Plan


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Types of Aggregate Plans Level Aggregate Plans

Maintains a constant workforce

Sets capacity to accommodate average demand Often used for make-to-stock products like appliances

Disadvantage- builds inventory and/or uses back orders

Chase Aggregate Plans

Produces exactly what is needed each period

Sets labor/equipment capacity to satisfy period demands

Disadvantage- constantly changing short term capacity


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Level Plan Example Level production rate= 28,000 units/7 periods= 4000 units

Level workforce= (4000 units x .64 std.)/160 = 16 people


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Chase Plan Example Chase hires and fires staff to exactly meet each periods

demand Period 1 = (500 units x .64 std.)/160 = 2 people, need to fire

16 people


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Types of Aggregate Plans cont Hybrid Aggregate Plans

Uses a combination of options

Options should be limited to facilitate execution

May use a level workforce with overtime & temps

May allow inventory buildup and some backordering

May use short term sourcing


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Aggregate Planning Options Demand-based options

Reactive:uses finished goods inventories and

backorders for fluctuations Proactive:shifts the demand patterns to minimize

fluctuations e.g. early bird dinner prices at a restaurant

Capacity-based options

Changes output capacity to meet demand

Uses overtime, under time, subcontracting, hiring, firing,and part-timerscost and operational implications


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Evaluating the Current SituationImportant to evaluate current situation in

terms of: Point of Departure

Current % of normal capacity Options are different depending on present situation

Magnitude of change Larger changes need more dramatic measures

Duration of change Is the length of time a brief seasonal change? Is a permanent change in capacity needed?


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Developing the Aggregate PlanStep 1-Choose strategy: level, chase, or Hybrid

Step 2-Determine the aggregate production rate

Step 3-Calculate the size of the workforceStep 4-Test the plan as follows:

Calculate Inventory, expected hiring/firing, overtime needs

Calculate total cost of plan

Step 5-Evaluate performance: cost, service,human resources, and operations


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Wiley 2010 12

Aggregate Plans for Companies

with Tangible ProductsPlan A:Level aggregate plan using

inventories and back orders

Plan B: Chase aggregate plan using hiringand firing


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Plan A- Level Using Inventory &

BackordersFirst

calculatethe level

productionrate

(14400/8=

1800)


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Plan AEvaluation Fill rate is 83.9%

Fill rate is likely to low

Inventory levels seem to be okay

Human resources fires two employees


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Plan BChase AggregatePlan Using Hiring and Firing

Using the sameproblem dataas previous

example,develop achaseaggregate planusing hires and

fires but noovertimeproduction.


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Plan BEvaluation

Plan B costs slightly less than the level plan.

Hiring demands ranges from two in November

to thirty-four in February Utilization is highest, 70.6%, in December and

even lower in the other months

Space and equipment are underutilized in everyother month of the plan


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Problem Data for Plans C, D, and E

45

67

8

910

111213

1415

1617

1819

202122

23

2425

26

2728

A B

Cost Data

Regular time labor cost per hour $8.00

Overtime labor cost per hour $12.00Subcontracting cost per unit (labor only) $60.00

Hiring cost per employee $250.00

Firing cost per employee $150.00

Capacity Data

Beginning workforce (employees) 60Service standard per call (hours) 4

Regular time available per period (hours) 160Overtime available per period (hours) 24

Demand Data (calls)

Period 1 2400Period 2 1560

Period 3 1200Period 4 2040Period 5 2760

Period 6 1680

Period 7 1320Period 8 2400

Total Number of Periods 8


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Plan CLevel Aggregate Plan withNo Back Orders or Tangible Product

Staff of 69 people creates excessive UT (averages 30% UT)

Cost per service call is $46.15($708,000 Divided by 15360 calls)


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Plan DHybrid Aggregate Plan UsingInitial Workforce and OT as Needed

Costs reduced by $77K and under time to an average of 20%

Cost per service call reduced to $41.13 (-$5.02)

Pl E Ch A t Pl f


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Plan EChase Aggregate Plan forNontangible Products Using Hiringand Firing

Total cost reduced by $114K over Plan F, utilization improved to100%, and cost per service call now $33.72 (-$7.41)

Workforce fluctuates from 30-69 people- morale problems

Solution?? Compare smaller permanent workforce, more OT??


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Aggregate Planning within OM: How it allfits together

Aggregate planning determines the resources available to operationsto support the overall business plan. It is critical that accurate demandforecasts be available (Ch 8) so that a reasonable production plan canbe developed. A company needs to determine the aggregate

production rate output required to determine the appropriate size ofthe workforce. After these determinations have been made, the company can

calculate its inventory levels, back-order levels, capacity requirements,and customer service levels. If the plan requires seven-day-a-weekoperations, appropriate staff schedules need to be developed (Ch 15).

The aggregate plan specifies the number of employees needed. Thisallows company to determine how much equipment and workspace isneeded, as well as to provide the input needed for developing aworkplace layout (Ch 9) within the operations area. Aggregateplanning provides the resources needed by operations to achieve thecompanys strategic objective.


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Aggregate Planning Across theOrganization

Aggregate planning, MPS, and rough-cutcapacity affection functional areas throughoutthe organization Accounting is affected because aggregate plan

details the resources needed by operations

Marketing as the aggregate plan supports themarketing plan

Information systems maintains the databases thatsupport demand forecasts and other suchinformation


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Chapter 13 Highlights

Planning begins with the development of thestrategic business plan that provides companydirection & objectives for the next two to ten years.

Sales and operations planning integrates plans fromthe other functional areas and regularly evaluatescompany performance.

The level aggregate plan maintains the same sizeworkforce and produces the same output eachperiod. Inventories and backorders absorbfluctuations in demand. Chase aggregate planschange the capacity each period to match demand.


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Chapter 13 Highlights cont

Demand patterns can be smoothed throughpricing incentives, reduced prices for out-of-

season purchases, or nonprime service times. The difference in aggregate planning for

companies that do not provide a tangible

product is that the option to use inventoriesis not available


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Chapter 13 Homework Hints

All problems are based on The BackPack Company.

Problem 13.1: level strategy allowing backorders. Calculatethe production rate and workforce level. Develop the plan,

calculate the costs, and evaluate the strategy. Problem 13.3-4: chase strategy. 3) Calculate the production

rate and workforce levels. 4) Develop the plan, calculate thecosts, and evaluate the strategy.

Problem 13.5: chase strategy with overtime. Calculate theproduction rate and workforce levels. Develop the plan,calculate the costs, and evaluate the strategy.

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