supply chain

What is operations management

Operations management focuses on decisions for the internal production of the firm’s products or services

An example would be the Amazon warehouse

Five key operational decisions:

Process: what is the optimal layout/flow? Labor or capital intensive?

Capacity: size of workforce? Availability of equipment?

Quality: quality level? How to monitor quality?

Inventory: when and how much to order

Supply chain: which supplier? Make vs buy? Partner or alliances?

Supply chain management deals with managing the flow of materials, information, and money across multiple organizations from the suppliers to operations to distribution to the final customers, along with the reverse flows

Operations and supply chain management deals with the sourcing, production, and distribution of the product or service along with managing the relationship with supply chain partners


  • Manufacturing (product management)

    • Produce tangible output

    • Can be produced in separation from the customers

      • It can be stored for some time

    • Homogeneity…products should be the same as others

  • Service

    • Produce intangible process

    • Require interaction with the customer

      • Perishable and time-dependent

    • Heterogeneous

OM is needed in what types of organizations: All of the above

Inventory management tends to play a more significant role in: manufacturing companies

  • Operations management is an important function in any organization

    • Cross-functional decision making

Looking at a car- the steering wheel serves as the strategy. The overall car serves as marketing. The Driver serves as HR. The gas serves as finance. The engine serves as an operation. 

OM in an organization


Why should you care about OM?

Powerful tools

  • Manage unexpected events

    • To achieve reliance to guarantee supplies of necessary merchandise, the well-functioning of our society relies on many supply chain and operational decisions

      • Supply management

      • Demand management

      • product/service designs

      • Supply chain design

  • E-commerce and Omni-channels are disrupting conventional business models

    • To compete in an omnichannel world, companies have to reconfigure and rethink their supply chains drastically

  • KPMG Global top of the Mind Survey for consumer and Retail Executives

    • As e-commerce and omnichannel disrupt conventional business models, this is what roughly 500 executives said:

    • 38% of executives said supply chain management is their top challenge

    • 42% placed supply chain management at the tip of their list for increased investment over the next 12 months

      • Followed by international expansion (32%), data analytics (28%), and digital strategy (28%)

  • Environmental and social responsibility considerations are becoming increasingly important

    • Sustainability = planet, profit, and people

    • Triple bottom line, co-production

    • Understanding where and how products and services are created is the key to becoming more environmentally and socially responsible

      • Eco friendly product management

      • Ethical and sustainable sourcing

      • Green manufacturing, packaging distribution, end-of-life product management (e.g, recycling)

      • Social impacts of business (e.g., labor practices)

  • Operations management activities are at the core of all business organizations

  • 50% or more of the jobs in the industry are operations management-related:

    • Customer service, quality assurance, production planning, scheduling, inventory management, logistics, 

  • All other functional areas are interrelated with operations management

  • Ceo’s from many successful companies with an operations background…gap, revlon, apple, p&g

  • Supply chain operations are in a wide range of industries….hospitals, army, retail, restaurants, etc.

How to make operations strategies and decisions

Operations strategy- a consistent pattern of decisions for operations and the associated supply chain that is linked to the business strategy and other functional strategies, leading to a competitive advantage for the firm

Business strategy 

OM Decisions, other functions

Competitive advantage

Operations strategy model

Corporate strategy: what business

  • Examples: tesla: accelerates the worlds’ transmission to sustainable energy, Walt Disney: making people happy

Business strategy: how to compete in the market

  • 3 generic business strategies (Porter 1980)

    • Differentiation. E.g, apple iPad, Tesla

    • Low cost. E.g, store brand products

    • Focus (geographical or product portfolio). E.g, Sweet Martha’s, Dyson

Operations strategy

  • Mission: connected to the business strategy and coordinated with other functional strategies

  • Operations objectives (competitive priorities): need to be quantifiable

    • Four common objectives

      • Cost: resources sued. E.g., as % of sales revenue

      • Quality: conformance to customer expectations. E.g., % of scrap, warranty cost

      • Delivery (quickly and on time): e.g., % of orders fulfilled from stock, lead-time

      • Flexibility (ability to rapidly change operations): e.g., time to product market

    • Other may also be added, e.g., innovation, sustainability, etc.

  • Strategic decisions

    • Process, quality, capacity, inventory, supply chain

  • Distinctive competence: the operations capability of a firm that outperforms its competitors, should match the mission of operations

Order winners bs order qualifies

  • Order winner: operations objective that differentiates one firm from another

    • Examples: quality (american express), price (IKEA), innovation (dyson)

  • Order qualifier: operations objective that must have acceptable level to get customer orders

    • Examples: responsiveness level necessary to be considered as a fast delivery service (FedEx Ground)

Cross functional strategic decisions

No one size fits all

Product Imitator

Product innovator

Market conditions

Standardized products, mature market, predictable demand, price-sensitive customers, high volume

customized/innovative products, emerging market, un-predictable demand, product feature sensitive customer, low volume

Operations missions and objectives

Emphasize low cost

Emphasize flexibility

Operations strategic decisions

Superior processes, dedicated automation, economies of scale, slow reaction to changes

Superior product, flexible automation, economies of scope, fast reaction to changes

Distinctive competence

Low cost

Fast new product launch, flexibility

Marketing strategies

Mass distribution

Selective distribution

Finance strategies

Low risk, low-profit margin

Higher risk, higher profit margin

Supply chain strategies

Cross functional strategic decisions

Environment and sustainable operations

  • Cross-functional efforts

  • All opportunities, including product development, sourcing, manufacturing, packaging, distribution, transportation, services, and end-of-life management

    Cross functional strategic decisions

New Product Design: why

  • NPD realizes the business strategy

  • NPD strengths the distinctive competence

  • NPD affects operations

    • Process: technology and availability of resources

  • Quality

  • Capacity

  • Inventory

  • Helps in marketing, engineering, resource (finance), manufacturing, etc.

New product design: how–Strategies for NPD

  • Technology push…we can make it

  • Market pull…we can sell it

Quiz

  • The technology push strategy relies heavily on cross-functional collaboration for new product development…TRUE

Technology push or market pull

  • Cocoa cola classic–technology push

  • Coca-cola zero–market pull

Strategies for NPD

  • Technology push (sell what we can make)

    • Develop superior technologies and products

    • Example: electronics

  • Market pull (make what we can sell)

    • Organize resources to fulfill customer demand

    • Examples: electronics

  • inter-functional view (a balanced approach)

    • most appealing, most difficult, cross-functional team involvement

NPD process

  • Well-defined procedures in company documents

  • Concept development

    • Idea generation and evaluation of alternative ideas

    • Evaluation of alternative ideas

  • Product design

    • Design of physical products

    • Design of the production process

  • Pilot production/testing

    • Testing production prototypes

    • Finalizing production process

    • Finalizing the ‘information’ package specifying details

Traditional (sequential) and concurrent approaches 

Supply chain collaboration

  • Collaboration with customers

    • Obtain information

    • Provide motivation and facilitator

    • Include customers as advisors 

  • Collaboration with supplier

    • Technical expertise

    • Capability

    • Capacity

    • Low risk

Modular design

  • High product variety + low component variety

  • Design basic product components or modules for assembling into multiple products

  • Reduce complexity and costs associated with a large number of product variations

  • Example: Volkswagen MQB platform

Quality function deployment (QFD)

  • Quality functional deployment (QFD): tool for linking customer requirements to technical specifications

  • House of quality

    • Customer attributes (CAs): from market research to define important product attributes 

    • Engineering characteristics (ECs): measurable technical specifications, match customer needs

    • Relationship between the ECs: trade-off, lightweight/durable, features/low price

    • Competitive evaluation: how are the competitors doing?

    • Target values of design

Forecasting

  • Why

  • What

    • Quantitative and qualitative methods

  • How

    • Quantitative methods

      • Time-series, casual

      • Forecasting errors

    • Qualitative methods

Forecasting: why

  • demand forecasting:

    • What we think demand will be 

  • Forecasts are used in all functional areas

    • Finance: budget planning and control

    • Marketing: sales forecasting

    • Operations: planning for capacity, inventory, labor scheduling, etc.

  • Poor forecasting costs money

    • To much: excess inventory

    • Too little: loss of sales

For very long-term forecasting, it is better to use qualitative forecasting

Quantitative methods

  • Time series models

    • Past data history is best predictor of the future

      • Look for patterns in the data

      • Forecast based on the time series (previously observed values”) of the variable to be forecasted

        • Moving average, exponential smoothing

  • Casual models

    • Forecast on the basis of relationships to other variables 

      • Regression approaches

Quantitate method: time series

  • Component of data:

    • Level - average

    • Trend - general direction (increasing/decreasing)

    • Seasonality - short term recurring cycles

    • Cycle - long term business cycle

    • Error - random or irregular component

Notations

Time series

  • (simple) moving average

  • Weighted moving average

  • Exponential smoothing

(Simple) moving average

  • N-period (Simple) moving average:

    • A forecast based on the simple average of the past N periods

      • Managerial decision: N

Weighted moving average

  • A forecast based on the weighted average of the past N periods

    • Managerial decision: N & Wi

Exponential smoothing

  • Weights past values

    • More weight given to the most recent period

  • Basic logic

    • New forecast = old forecast + error judgment


The cumulative sum of forecast errors—the answer should be on the smaller side…as small as possible

Smaller n equals more responsiveness

Choices of parameters 

  • Responsiveness (sensitive to a demand change)

  • Stability (remain smooth to ignore random fluctuations)

Assessing forecast Accuracy: Forecast Error

  • forecast are almost always wrong – How accurate?

  • Estimate forecast error to:

    • Monitor erratic demand observations or ‘outliers’

    • Determine when the forecasting method must be improved 

    • Determine the parameter values that provide the forecast with the least error

Advanced time series forecasting

  • Adaptive exponential smoothing

    • The smoothing coefficient () is varied

  • Mathematical models

    • Linear or nonlinear

  • Box jerkins method

    • Requires about 60 periods of past data

Casual forecasting models

  • Cause and effect model

    • Examples

      • Use population to forecast newspaper sales

      • Use supply chain data on inventory level to forecast flat-screen TV sales

  • The general regression model:

    • ^y = a+bx

  • Other forms of casual model

    • Econometric, input-output, simulation models

Selecting a forecasting method

  • User and system sophistication

    • People are reluctant to use what they don’t understand

  • Time and resources available

    • When is a forecast needed?

  • Use or decision characteristics

    • Scheduling decision? Facility expansion?

  • Data availability

  • Data patter

    • Level? Unstable?

Qualitative forecasting methods

  • Based on managerial judgment when there is a lack of data

  • Major methods:

    • Delphi method

      • 1. Summarize answers (anonymous)

      • 2. share

    • Market surveys

    • Life-cycles analogies

    • Informed judgment (naive models)

Collaborative planning forecasting, and replenishment (CPFR)

  • Aims to achieve more accurate forecasts

  • Share information in the supply chain with customers and suppliers

  • Compare forecasts 

    • If there is a discrepancy, look for a reason

    • Agree on the consensus forecast

  • Works best in B2B with few customers (e.g., a small number of large retailers)

Why hold inventory: benefits and costs

How to manage inventory: EOQ…how much?, when?

Why hold inventory

  • Inventory: stock of materials used to facilitate production or satisfy customer demands

  • Purpose of inventory:

    • To protect against uncertainty (safety stocks)

      • Demand may be higher than your forecast

      • Supply may be disrupted

    • To allow economic production and purchase (cycle inventory)

      • Quality discount

      • Fixed cost

    • To cover anticipated changes in demand or supply (anticipated inventory)

      • Upcoming surge in demand

        • To avoid large investments in capacity

    • To provide for transit (pipeline inventory)

      • Items in the transportation process

Why not hold inventory?

  • Holding inventory can be costly

  • Tangible costs: storage space costs, spoilage/breakage, pilferage, insurance, taxes

  • Intangible costs: opportunity cost, devaluation, obsolescence

  • Procurement can also be costly

    • Administrative costs

    • Transportation costs

    • Manufacturing set-up costs

How to manage inventory

  • Inventoried decision: 

    • How much to order (order size)

      • Fixed order quantity (Q)

    • When to order (order frequency)

      • Reorder point (R) 

EOQ model

  • Two basic types of costs

    • ordering/set up costs: logistics, handlings, contracting, inspections, setup costs (for production)

      • A fixed payment per order

    • holding/carrying cost: warehouse, interest and taxes, insurance, obsolescence

      • A variable payment depending on the holding volume


The cost of shipping per order is ordering cost

The cost of drafting a purchasing contract is ordering cost

The cost of capital to finance the inventory (e.g., interest payments) is holding cost

The cost associated with inventory obsolescence is holding cost

When ordering cost increases, we should increase the size of each order

When the holding cost increases, we should decrease the size of each order

When the size of each order increases:

  • Holding cost: increase

  • Average unit ordering cost: decrease

How much to order/produce?

EOQ model

  • Assumptions

    • Demand rate is constant, recurring, and known

      • D: demand rate (e.g., units per year)

    • Lead time is constant and known

    • Items or materials re-ordered in a lot or batch

      • S: ordering/setup cost per order place (e.g., dollars per order)

    • Stock-outs are not allowed

    • Unit cost stays constant 

      • C: unit cost (e.g., dollars per unit)

    • Only one type of items is considered

  • Goal:

    • How much to order (ordering size): Q

    • When to order (reorder point): R

EOQ model: Cycle Inventory


EOQ: Total cost

EOQ: a simple exercise

  • Demand = 200 units/year

  • Cost of product A

    • S = $100/order, H=$2/unit/year

  • Strategies

    • Q = 10

  • Total annual cost of inventory?

Economic Order Quantity (EOQ)

  • Q = optimal ordering size

  • D = demand rate

  • S = set up/ordering cost (i.e., cost per order placed)

  • H = holding/carrying cost


When to place a new order?

  • Meal management kit 

    • D = 1 box/day

    • Lead time = 2 days

  • You should reorder when the remaining stock = 2 boxes


Reorder point 

  • Quantity (how much to order): EOQ

  • Timing (when to order)?

    • Reorder point: the inventory level at which a new order should be placed to avoid future shortage

    • To account for the lead time of delivery

  • Reorder point (R) 

    • = demand during ordering lead time

    • =lead time (L) X demand rate (D)



EOQ: example

  • The 3001 company sells some textbooks with an average demand of 500 units per year. The ordering cost is $30 per order placed. The company has to pay a holding cost of $12.5 for each book

    • What is the optimal ordering size for the company?

    • If the company is able to negotiate and bring down the ordering cost to just $25, how does this change the ordering size?

  • The replenishment lead time is typically 2 weeks (assume the bookstore opens 50 weeks a year). What is the reorder point?

    • Whenever inventory drops to 20 units, a new order is placed

Capability planning is important

  • Capital intensive

Hierarchy of capacity planning

  • Scheduling: short-term planning, 0-12 months

  • Aggregate planning: medium-term planning, 6-18 months

  • Facilities decision: long-term planning, 12-24 months

Capacity: definition

  • Maximum output that can be produced over a given period of time

    • Theoretical peak capacity

      • Outputs 

      • Physical assets available

    • Effective capacity

      • Downtimes, shift breaks, interruptions

      • Should be used for planning

Capacity: utilization

  • Actual output/capacity x 100%

  • Capacity is seldom at 100% utilization

  • Utilization can > 100%: overtime, additional shifts, rush order

  • Capacity cushion = 100% - Utilization

Long-term capacity planning” facilities decision

  • Strategic perspectives

  • Cross-functional coordination

  • Considerations

    • Predicted demand

    • Cost of facilities

    • Competition Landscape

    • Business strategy

    • International considerations

Five crucial questions in facilities decisions

  • How much capacity is needed?

    • Large cushion

    • Moderate cushion

    • Small cushion

  • How large should each facility be?...economies of scale

  • When is capacity needed?

    • Preemptive strategy

    • Wait and see strategy

  • Where should the facilities be located?

    • Quantitative factors

      • ROI, NPV, Transportation, Taxes, Lead times

    • Qualitative

      • Language and norms, attitudes among workers and customers, proximity to customers, suppliers & competitors

  • Why types of facilities

    • Product based facilities

      • Facilities for one family or types of product or service

      • (economies of scale, transportation costs)

    • Processes-focused facilities

      • Use a few technologies, frequently used to produce components or subassemblies

    • Market-focused facilities

      • Facilities located near markets 

      • (transportation cost, service, international trade)

    • General purpose facilities

      • flexible

For low-margin products (printer paper), it is better to keep _______ for production

  1. Large cushion

  2. small cushion

Medium-term capacity planning: aggregate planning

  • Supply

    • Capacity: size of workforce, over/under time, part-time/temporary, outsource, subcontracting, cooperative arrangements

    •  inventory

  • Demand

    • Volume of demand

      • Pricing, advertising and promotion, backlogs and reservations

    • pattern/timing of demand

      • Pricing schemes, development of complementary products/services

Sales and operations planning

S&OP planning

  • Accounting: cost analysis

  • Finance: Investment

  • Operations: forecast, inventory, capacity, current orders

  • Marketing: forecast, sales plan

  • Human resources: personnel planning

Aggregate planning strategies: level vs. chase strategy


EOQ model

  • The demand rate is constant, recurring, and known

  • Lead time is constant and known

  • Items or materials re-ordered in a lot or batch

  • Stockouts are not allowed

  • Unit cost stays constant