What is a spaghetti diagram?

A spaghetti diagram, spaghetti plot or spaghetti chart is the drawing depicting the physical flow or route of:

  • a part, raw material in a workshop or factory
  • a human worker in his/her work environment
  • a patient in his/her journey in a hospital
  • nurses in their station
  • a file or paperwork being handed over across offices
  • etc.

The drawing of the journey will show how intricate the route is, looking like a plate of spaghetti, hence the name.

Spaghetti chart, what for?

Spaghetti (1)These charts are used to analyze the distance covered, the going back and forth to some place, the wasted time in motion and/or transportation (muda).

People are often unaware what distances they walk in a day and management is unaware of the time spent moving around the place wasting time and energy.

Spaghetti chart are useful to redesign a layout or reposition some equipment in order to reduce the unnecessary walking time and fatigue, which is only waste.

Sometimes it is the order of steps in a process that can be changed for the sake of efficiency.

A spaghetti diagram is a welcome sidekick to Value Stream Mapping, as the later maps the conceptual route through a process while the spaghetti chart shows the actual (or future) physical one.

How to draw a spaghetti chart?

Spaghetti charts depicting the actual situation should be based on real observation. On a prepared sheet with outlines of the facility, machines, equipment, etc. the observer traces the lines as the observed object/person moves from one spot to the next.

Tips and tricks

  • The drawing should be more or less on scale, so that it is easier to estimate the total distance covered.
  • If scale is unknown, count the steps when walking and estimate an average stride length. This will help estimate all the distances and the accumulated distance.
  • When the trail is going and coming forth, draw each line separately in order to count the frequency per time unit (e.g. per quarter, per hour, etc.). it will also help to estimate the total distance by multiplying the segment length with frequency.
  • Try to depict the route faithfully. Do not draw straight lines through walls as I saw once because my explanation was not specific enough!

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VSM start on (false) assumption


Chris HOHMANN – Author

Value Stream Mapping (VSM) is a great tool, that got really popular and stands as a one of the icons of Lean.

In a nutshell, Value Stream Mapping is the schematic description of physical and information flow of a process or a value chain. It helps understanding the current situation and analyzing the causes of issues and limitations. VSM is followed by a design of the desired future state, called Value Stream Design (VSD). The third implicit part of a VSM-VSD is the action plan, made of the necessary actions for changing from current situation to the desired future state.

VSM is therefore an excellent trigger for continuous improvement and used as such in Lean initiatives.

What lean enthusiasts using VSM look for is a smooth, fast and direct flow from customers’ needs or desires to customers satisfaction, using only the very necessary resources. This requires the process supporting the flow to be as free of wastes as possible.

Wastes mean Muri, Muda and Mura, more about this >here<

It seems reasonable then to (re)visit the process and hunt down any waste in order to improve the flow.

Doing so is making an assumption, mostly unspoken and even unconscious, that the actual process is really useful and needs/deserves improvement.

Yet most of the lean enthusiast take a shortcut on the scientific thinking promoted by Lean, jumping too fast on Doing (read Mapping in this case) without giving enough time, if any, on Planning.

The Plan phase of the PDCA is meant to pose a hypothesis and to design an experiment carried out during the Do phase and assessed for validation or invalidation in the Check phase.

It therefore happens, more often than believed, that an unnecessary process gets attention, time and resources allocated for improvement when what was is really needed is simply to get rid of the whole process!

How can a process be useless?

It is common to setup a process in order to overcome a problem and literally forget to remove it once the problem is solved. Many processes are cluttered with sub-processes and procedures once created to bypass or overcome a problem that remain in place, consuming resources for absolutely no value creation.

In order to avoid such kind of embarrassing creation of muda (Value Stream Mapping an unnecessary process), each process candidate for a VSM should first be analysed for its purpose: what is the goal of this process? what problem this process is supposed to solve?

If there is no good reason for the process to exist, no need to map it, go for discarding it. (Note: good reasons may include “mandatory by regulation”)

For another variation on this subject, you may like to read VSM Pitfall: unnecessary process

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Value Stream Mapping is a tool for pivoting

“Pivot” has become a buzzword in business, referring to a shift in strategy or a significant change made in product, service or business model as a result of experiment.

When a solution or an assumption does not lead to or deliver the expected outcome, a significant change may be required to adjust to the reality instead of sticking too long with the flawed parameters.

Pivoting suggests a change of direction and this is the intent with Value Stream Mapping (VSM): pivoting from vertical to horizontal.

VSM reveals the physical and information flows across an organization (horizontally) end to end, which is “pivoting” from the traditional point of view which is vertical, divisional or departmental way of considering organizations and responsibilities.

By pivoting, VSM reveals all the waste created by local optimizations and required adjustments at interfaces, e.g. duplicate inventories, buffers, different batch sizes or different rules and policies, etc.

VSM is a tool for pivoting or shifting the point of view, the way we look at value creation with the customer waiting at the end of the value stream.

Together with the improvement potentials revealed, Value Stream Map enables pivoting: changing the process, the product or the business model in some extend.

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March 2015 review of February


Chris HOHMANN – Author

February is the shortest month of the year. It’s a poor excuse for my few February postings I know, but lack of time is nevertheless the primary cause of this historical low number of posts on my blog. Not that February wasn’t rich of experiences and inspiration, but turn ideas into written lines requires some time and the state of mind you may call inspiration.
Among things I heard or saw in this short month:

  • the fallacy of what they call Six Sigma
  • 3D printing, the unknown threat
  • a kick in the a*s as energizer (?)

The fallacy of what they call Six Sigma

How many organization pretend to go the Six Sigma or Lean Six Sigma way and in reality are not?

I came across one more displaying explanatory posters and having Six Sigma terms in their jargon, yet the most buoyant promoter did not understand my question about standard deviation and was suddenly uneasy when I asked him about his mastery of basics of statistics.

In fact, as so many times, what is called Six Sigma is just about using DMAIC as a structuring framework. In this plant, local managers admitted that the Measurement phase, which could make good use of some true Six Sigma tools, is the least mastered.

Another company with a Lean-Sigma dedicated bureaucracy uses ‘IPO’ instead of SIPOC, obviously not feeling necessary to care about Suppliers nor Customers.

Indeed, this bureaucracy does not seem to care much about its internal customers and focuses mainly on its own occupation, consistently with its focus on ‘IPO’; Input, Process and Output.

I have seen numerous others using Six Sigma lingo but in reality going for lean tools, generally nothing more than some partial 5S to clean up the initial mess and a fashionable VSM as wall ornament.

3D printing, the unknown threat

Visiting an aerospace equipment maker, it was a real pleasure to see the manufacturing of high-tech art pieces. It takes a great deal of top-notch machinery and machining time to go from the raw chunks of metal to the finished parts. As usually in this industry I try to guess the weight of the parts knowing there is no correlation between their size and volume and keep being amazed by the geometric complexity of the designs.

I asked the proud line manager if additive manufacturing (‘3D printing’) was on its way into his workshops. He did not understand my question, obviously not knowing what I was talking about.

The new techniques threatening his beloved business of cutting away metal with costly machines are unknown to him. He worries about training a new generation of turners, unaware that he’d better look for young techs at ease with CAD-CAM and programming.

A kick in the a*s as energizer

I am no promoter of old fashioned “management” methods consisting of bullying or even physically abusing people, but from time to time a (virtual) kick in the a*s is indeed an energizer.

Alas, the energizing effect is not long lasting. One team member laughed about sore bottoms and all resumed as usual.

Considering the resilient properties of the human bottom regarding kicking (all this being figurative), I let top management keep kicking and chose to go for rational demonstration of the necessity to improve faster, selecting the proper metrics as KPIs, the first improvement step.


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VSM Pitfall: unnecessary process

Value Stream Mapping (VSM) is probably the main analysis tool and the most used in the lean toolbox. Easy to understand and handle, VSM is the starting point of improvement workshops and kaizen events. It helps focusing on wastes and improvement potentials in any process.

The ease of use and popularity of VSM make them flourish on shop floor. What seems good news for continuous improvement at first glance may not be all that positive.

> Lisez-moi en français

Remember: while improvement opportunities are literally infinite in any environment, resources are always limited: time, availability, means…

Therefore, before rushing into Value Stream Mapping, it is necessary to focus on chosen areas and topics in order to make meaningful improvements and avoid wasting limited resources.

The worst waste would be to Value Stream Map a useless process, which would mean Map, analyze and improve a process that should be eliminated in first place.

This happens more frequently than one would think.

Countermeasures to problems and the 3% devious

Many existing processes in an organization are countermeasures and responses to problems. These problems were eventually solved once, but the process is still in place.

Should one therefore seek to optimize it or can wouldn’t it make sense to eliminate it altogether?

In the absence of statistical data on the occurrence of the problem, which is the most common case, the answer is tricky. Moreover, advocates of the process will argue that it is precisely because the process is in place no problem reappeared.

If these problems still show up in a low occurrence, are the costs of maintaining a process to prevent, resolve or dampen them consistent regarding the effects of these problems?

If not, all things being equal, isn’t it better to eliminate this process and support the relative lower cost of infrequent problems?

Finally, if the recurrence of problems is frequent, the process does not work and the right question is less about optimizing it than to invest in eradicating the problem.

An order of magnitude, probably more symbolic than real, is the management of 3%, a term due to Gordon Forward, former CEO of Chaparral Steel, which means the countermeasures in place are there for 3% of employees with deviant behavior, which penalizes 97 % of those keeping to the rules.

If a process exists because of 3% of the employees, it hides a management problem.

Should one therefore seek to improve such process?

Would it not be better, before drawing a single VSM line, to question if not simply eliminate this process?

Lack of coordination and strategic alignment

The second case is that of companies / organizations / corporations which do not coordinate lean initiatives, let shop floor / operations take local initiatives.

People in these lower levels reason and act according to their perceptions, they do not have the necessary global view nor the “zoom-out” to embrace the situation as a whole and see the uselessness of the process. They lack a kind of VSM of VSMs.

I remember at least two cases, industrial groups whose central lean offices asked the subsidiaries to run pilot improvement workshops on a process of their choice. Each workshop was required to start with a Value Stream Map.

In both cases, central lean offices had no strategy nor global plan. By default, they launched local bottom-up initiatives and assumed the people involved to get self convinced by the power and usefulness (read necessity) of a Lean transformation.

The potential problem with this approach is the risk to encourage enthusiastic launches but later put local initiatives on hold, possibly discard the improvements and order to redo on an other process, for the sake of alignment to strategic objectives or global coordination.

One can imagine all the frustration and loss of confidence of local actors if this should happen. They worked on improvements, accepted to change the way to achieve their tasks and possibly saw real improvements before a remote authority orders to stop and redo something else.

Not only all  resources used in pilot workshops would have been wasted – even so it can be called investment in training – but the credibility and sustainability of such approach would surely be impaired. It certainly will be difficult to motivate again these people for another workshop.

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