Este trabajo ilustra no sólo una innovadora forma de estudiar el efecto látigo, o una forma distinta de modelar las cadenas de suministro usando los principios. Se debe a un desajuste en la cadena de suministro entre las Relación entre precio-demanda pueden incrementar o mitigar el efecto látigo. Efecto Latigo Solución CPFR Planeación agregada. Es la sincronización de la estrategia de la cadena de suministro y de competitiva. Causas.

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Operations Management, Manchester Busines School. University of Manchester, UK. This is a case study about the modelling of a supply chain decision structure of a Mexican bottling company. We find that by modelling the information and decision cadna of supply chains, it is possible to identify managerial policies and information flows that distort and amplify market demand signals.

In the second part of the paper we use two scenarios to analyse various changes in policies. This paper illustrate not only an innovative form to study the Bullwhip Effect nor only a different way to model supply chains using System Dynamics, but also it establishes a relationship between information structures, decisions rules, and demand distortion in supply chains.

System dynamics, supply chain management, case study, bullwhip effect. The study of supply chain dynamics is about companies operating manufacturing supply chains of multiple echelons lxtigo to limited production and distribution capacities. At each echelon, operation managers receive orders from a downstream echelon and try to fulfil them by taking two decisions: Order policies are based on experience, operational strategy rfecto information availability.

Order fulfilment is constrained by production capacity, transportation capacity and inventory availability. Supply chain systems have mainly two time delays: The supply chain dynamics problem consists in that given a set of order policies from managers at each echelon, market demand signals will be distorted and amplified the Bullwhip Effect through the echelons. The objective of supply chain dynamics problems is to minimize operational costs derived from those distortions and amplifications by improving managers order policies.

In the context of the supply chain dynamics problem, Forresterand Sterman, have explored the impact of time delays. However, Forrester and Sterman’s approaches fall short of study the supply chain dynamics because they use a predefined flow of information and management rules which are not longer valid for companies that use information systems. PCNA grew faster than its largest competitor. They are sure that innovation was the driver of that growth, because in fact PCNA brought an array of new products to the marketplace.

Much of that innovation focused on carbonated soft drinks Figure 2. Pepsi Twist, which is Pepsi with a hint of lemon, helped the growth in their cola business. Within 30 days of launching Pepsi Twist in the US, Pepsi bottlers had sold more than 10 million cases. And additional volume growth came from products under the Dole and SoBe brands. For this strategy it is central to keep the continuous expansion of its product portfolio.

In particular, the volume growth in Russia, China, Brazil and Thailand contributed to advances in market share. Here too, innovation was a big factor. Extensions of the flagship Pepsi trademark helped to drive growth in a variety lxtigo local markets.

The launch of Mountain Dew contributed significantly to growth in Russia.

… more than classic ‘beer game’.

Combining the general and administrative functions of these businesses around the globe yields very substantial cost savings. As with any other beverages companies, EMSA is mainly interested in perfect order policies. That is, keeping inventories in all possible retailers, since product substitution against the competition is very frequent. In their business, product presence at sales point is translated into sales. They purchase sugar based on price. Every year they select a small set of suppliers from a pool of possible vendors.


Sugar price varies according to market. In Mexico most of the producers are state owned. There is a minimum amount of sugar to buy on a monthly basis of Ton. Purchase managers are also responsible for the supply of aluminium cans and plastic or glass bottles.

Purchase managers generate a supply plan once every month and at least one month in advance. Pepsi uses its own fleet of trucks to pickup the materials from some suppliers. The following is an extract from the interviews with the purchase manager: In this warehouse, there are components that are managed against schedule orders: We have a minimum stock inventory policy We order based on a maximum and minimum with small corrections according to the real demand We have to take into account maintenance, and order in advance when needed.

We have also orders to be confirmed on a monthly basis.

implexa – supply chain game and simulation software – home page

Every week we check our inventories and pay their invoices. When a new product launch happens, we have to work closely with designers from PepsiCo Mexico. The designs are provided from d corporate headquarters, we then forward them to our label suppliers along with an initial purchase order My main problems with Logistics are that they never give me the production programme!

When we interviewed the production manager, apart from being proud of their excellence awards in quality and achievements in reducing waste, he pointed out that one of the problems was the obsolescence of product due to shelf life. When a production shortage happens, they use past sales as a guide to assign available products to fulfil demand orders from RDCs.

Tatiana Lara

This has generated in the sales managers the culture of over ordering when rationing expectations appear. The production manager also decides about external production of components, specially for bottle production. I have my own policy of inventories. I always try to follow my policy, which is optimal. I look at the inventories once a week and from there I make a weekly plan: How much do I require for every product for the next week based on my forecast and stock position?

How much is my excess or shortage? Now, in [the case of] plastic and glass bottled products, because we never have high [expensive] inventories, I need to be very flexible in scheduling.

But that is not the case of cans; [there] I try to make long production runs per week. In this way I can optimize the number of changes and setups, for different flavours and sizes They have more thansales points.

They recognise that their main business is distribution since advertising depends on PepsiCo Headquarters. The average level of education reached by a salesman is secondary school. In principle, the forecast is produced by operational managers using econometric standards, and the sales managers are responsible of fine tune it with expected demand volumes per zone and by product.

I believe that we never follow them We produced that forecast for 4 or 5 months directly, creating the forecast from our sales estimations based on the “last month sales” and we multiplied it by a factor month by month We finally agree that forecasting was going to be again a responsibility of production, but under the assessment of the sales department Everything goes together with sales I believe that production used to do a good job, same as sales Their main problem is distribution, in particular related to the administration of different sizes of trucks and vans, and the use of third party transportation.


Given the nature of the System Dynamics methodology Sterman ; Lane ; Doyle and Fordthe model will not emphasise the detail of the Supply Chain network. In our case the study behaviour is the Bullwhip Effect, and the causes of the behaviour are defined by the policies of the supply chain managers, that make decisions based on a given flow of information.

Therefore, the model is limited in detail but not in meaning since our analysis of distortions is of an aggregated nature. Particularly, a model of this nature does not need to detail multiple plants or DCs and products to analyze the information use and decision making process of managers.

The model lays emphasis on the modelling of policies of the supply chain managers that may be based on their own experience or knowledge.

We make explicit the use of information flows and their sources. The model shows the availability and reliability of the information through the information systems used by the business. The model can also be used to analyze the congruency of decision makers with respect the information systems. We have selected for model validation and calibration parameterization the historic demand for the year Based on this demand we have modelled the supply chain dynamics by including heuristic policies as described by the supply chain managers during our interviews.

The model shows the main aggregated behaviour of inventories, differences between plan and execution and the resulting service level. The decision making happens at the beginning of every week, when managers look at the information systems and decide how much to order upstream. Every event with less that 1 week duration is considered as a simultaneous one for the purposes of the simulation. The time step unit is weeks and all order quantities are in finished goods equivalent units.

Figure 5 shows the model diagram for the Pepsi ml. Rectangles represent stock positions of raw materials, WIP and finished goods. As can be seen, in the model we have defined four stock positions in the model: The raw material stock units represent all the components needed to build one unit of finished goods.

Variables are represented with circles, and constants with diamonds. The variable value or constant is communicated to another variable by drawing a single arrow.

Some variables represent decision makers managers and include the use of information inputs into a function that ends with a numerical decision e. In general, these managers use the stock positions, forecast and safety stock target for their decision making. The safety stock policies, or safety stock target, are constant values. Coverage policies are different for raw materials and finished goods mainly because there is a delay of more than one week from purchase to delivery of materials.

EFECTO LÁTIGO by Mariam Trejos on Prezi

The model can include promotional events and the introduction of new products, in such a way that the forecast is not only influenced by past weeks but also by marketing campaigns. Also some special seasons where some production needs to be allocated in advance to avoid production overload.

The model is described in mathematical form as follows. First the state al are defined by: