Lean Management System – A Process Interaction Matrix

Lean Management System – A Process Interaction Matrix

“There is nothing so useless as doing efficiently that which should not be done at all.”
Peter Drucker

Mark Kaganov

Annex SL, element 4.4, management system requires that “The organization shall establish, … management system, including the processes needed and their interactions…”  What do companies often do to respond to this requirement?  Businesses document “interactions” in charts similar to the one below:

This “interaction” chart is called “thirty thousand feet view.” It does get your auditors out of your heir, but other than that, it does not do a thing to enhance your business performance. 

The next popular representation of interactions is the flow chart with the “Yes” and “No” decision steps.  The receiving department signs the papers, logs the product into the MRP system, and sends it to the inspection.  The inspection tests the product and, when accepted, sends it to the warehouse.  When the product fails, it goes into the review and disposition process. 

This type of chart may be helpful in training for a specific operation.  But, again, it does not show the interactions with the processes outside of the operation.  If we were to extend this type of diagram to include links with other processes, we would end up with an unreadable “spider web” type relational diagrams similar to the example below:

These diagrams are informative for small clusters of processes but totally useless for the entire management system.  As you can see from the chart, the number of relations between the processes grows exponentially.  The Figure shows the number of interactions, in both directions, depending on the number of processes involved:

  • Two processes – 2 interactions,
  • Three processes – 6 interactions,
  • Four processes – 12 interactions,
  • Five processes – 20 interactions,
  • and so on.

It looks like this progression follows the function:
The interactions = the processes squired – the number of processes

Example of three processes:
Interactions = 32 – 3 = 9 – 3 = 6

When we apply this formula to the real world with some twenty-five or thirty processes, we can see that the number of arrows going up and down, and left and right will grow to some six hundred plus links.  And this is not yet counting conditional relations.  A conditional interaction is when a process not necessarily receives input or provides an output, but MAY receive input or MAY provide an output.  So, now what?  A brick wall?  No, no, do not give up!  Look what I found!  Let’s arrange our processes in a cross-sectional format.  We will list our processes in the rows and the same processes in the columns, something like this

Since a process cannot interact with itself, so we will “X-out” all intersections of the same processes:

Now, using the “>” symbol, we can show that Process 1 provides input into Process 2 and Process 3.  Likewise, the “<” symbol indicates that Process 3 provides input into Process 2.  You also may notice that there is a shaded “<” symbol.  This character shows that Process 5 MAY provide input into Process 4.

Let’s take a look at a real-life example of the use of such a technique:

The Matrix shows:

  • The context provides input into the Documentation Management because the context needs to be documented (well, the standards do not require documentation of the context, but it is just a good business sense),
  • The Documentation Management provides input in the context, specifying how the context is documented,
  • The Document Management provides input into the NC-CAR process, specifying the format for the NC-CAR process,
  • The NC-CAR MAY provide input into the Documentation Management, as NC-CAR may identify needs for changes in documentation,
  • And so on.

In October 2004, Quality Progress Magazine published my article with this model of the Process Interaction Matrix.  Since then, dozens, if not hundreds, of companies adopted this approach, probably the most comprehensive technique to document management system processes’ interaction.  Here it is, our Lean Process Interaction Matrix, updated to the latest revisions of the standards.

There are a few distinctive features in this model:

  • It can accommodate without limitation any number of processes,
  • You can also use it for individual operations, and
  • It allows us to define conditional interactions.

Speaking of individual operations, one of my customers got rid of their sixteen-page design procedure and replaced it with the Design Process Interaction Matrix and the Design Project Plan.

Not once I heard skepticism about the usefulness of the documenting process interactions.  Well, understanding how processes relate to each other helps better planning of your company’s deliverables.  For example, suppose your Production Planner issued you seven Work Orders for today, and you know that you have resources only for six. In that case, you may consider flagging this disconnect to align the processes better.  Many companies use quantitative process flow maps precisely for this purpose. 

Understanding how processes relate to each other helps better planning of your company’s deliverables.

Originally, Quality Progress Magazine published this article in October of 2004. This updated version reflects on the ISO 9001 2015 standard requirements and considers recent developments in this helpful technique.