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Burgers or Subs? Batch and queue vs Flow.

Posted by Stephen Parry on Oct 9, 2012 2:24:43 AM

Creating the flow of value, Let the work dictate the design

I am often amused by so many 'Lean' experts citing the McDonalds fast food system as a 'Lean' system when in fact its an excellent 'mass-production' system. It does not even qualify as 'fake-lean' because its not trying to pass itself off as Lean. Rather its the confusion in the minds of the so called Lean experts. So what are they getting confused about.? I think it's probably the concept of on-demand, flow and standardization.

In the McDonald production method the products do seem to flow, using the ordinary understanding of that word, in-fact its just a batch and queue system, it's not one piece flow, that is the product is moving continuously with only one item at any position at any one time.

Misunderstanding standardization: McDonalds have a standardized process and  its designed to deliver a standardized product with little variation and little customer influence over what is produced.

Now there is nothing intrinsically wrong with McDonalds, I like then now and again, probably too often for my wife's liking. What I am taking exception to is calling it Lean. The following article (extracted from my book Sense and Respond: The Journey to Customer Purpose Macmillan 2005) compares a Mass production fast food system with a Lean Fast food system.

I hope this clarifies what is meant by Standardization and Flow in Lean terms. If you have any comments or questions please post them.

Creating flow is an important feature of an on-demand ‘pull’ service (Womack and Jones, 1996). The concept is simple, yet the practice can be difficult.

Usually the current organisation is based on a batch-and-queue system, whereby work gets stockpiled and moved around departments. In manufacturing this can be seen in the form of inventory waiting in staging areas; in services it can be seen as sorting and prioritising service requests, tiered services such as ‘first-line, second-line’, sorting invoices into batches for processing, and so on.

A simplified illustration of both approaches can be offered in the ways two fast-food chains have approached the task of preparing food and serving customers.

Most fast-food burgers chains follow, to a large extent, the batch-and-queue principle. In one such chain each worker is assigned a particular task in the production and serving process. Food is cooked in batches, usually according to a forecast based on daily trends and the manager’s intuition. The kitchen workers prepare ingredients to a forecast and wait for instructions to cook it. The food is then placed in a staging area for frontline staff to serve customers.

If the forecast is wrong, then either too much food is produced, resulting in waste, or not enough food is produced, resulting in lost revenue. Production in expectation of customer demand can result in high levels of waste, so staff in this situation are targeted on meeting demand and minimising waste. The customer is offered a choice of standardised products and combinations.

If the customer wants any other variety, then this can only be achieved as a special request – in effect, production by exception and priority. This circumvents the main production process, usually leaving this customer waiting much longer than other customers even though she or he is now getting special treatment. In this scenario, product standardisation reduces variety, thereby simplifying the production process.

Contrast this kind of flow with the one-piece flow achieved by another fastfood company, which makes sandwiches and ‘subs’. When you enter you are immediately offered a number of varieties of bread and rolls from which your meal will be constructed. You are invited to choose what ingredients you wish.

You are free to look at the ingredients and to make choices based on what appeals. You give your order; and the ingredients you have chosen are placed in the sandwich, which is then passed to another worker who finalises the order and takes the money.

In this situation, the ‘sandwich’ flows as one piece, from the start of the operation to final completion. The customer is involved in every part of the process. Variety is built in and does not need special off-line treatment. There are no staging areas where food could go to waste: all food is produced on demand, not to forecast.


One piece flow

All the workers are involved with the customer and with the creation of customer value. This enables workers to be involved in helping the organisation select new ingredients – they are closer to understanding particular customer needs. This allows the organisation to keep changing the variety offered, almost on a daily basis. Waste is minimal, because every order has a customer and is produced to her or his requirements.

What has been standardised, therefore, is not the product but the production method.

Both approaches have been designed to solve a fast-food problem, yet the approaches are based on two quite different sets of principles. The mass-production approach – standardisation and the elimination of variety, functionalisation, batch-and-queue, and working to forecast – makes change difficult because the whole machine and the connecting procedures need modification and re-training.

In contrast, the on-demand flow system, in which variety is designed-in, not designed-out, produces continuous flow. The customer is involved in the production process at every stage, and workers are engaged with the customer and can learn her or his likes and dislikes. Change is adaptive and daily.

From this simple illustration, it is evident that the second company is better placed to create variety on demand and to continually adapt to changing customer needs and even to local tastes. Both these companies are successful, but in a world where customers are demanding more variety, even successful organisations have to ask themselves, ‘What do we need to do to maintain success? Are our current operating principles likely to cause us to lose competitive advantage?’

Extract from Sense and Respond: The Journey to Customer Purpose. Stephen Parry

©Stephen Parry 2012 All rights reserved.

Topics: Sense and Respond Book