Do Rules Decompose to Processes or Vice Versa?

Ronald G.  Ross
Ronald G. Ross Co-Founder & Principal, Business Rule Solutions, LLC , Executive Editor, Business Rules Journal and Co-Chair, Building Business Capability (BBC) Read Author Bio       || Read All Articles by Ronald G. Ross

In this one-per-month special 'notepad' series, I am taking a quick look at important issues facing practitioners who are seeking to understand and apply the business rule approach for capturing business requirements and developing business systems.

Modeling real-world things requires a layered approach for processes -- recursive decomposition of high-level processes into lower-level processes.  Does the same apply to rules?  Is recursive decomposition of rules possible?  If so, would such recursive decomposition of rules ever lead to lower-lever processes?  Would recursive decomposition of processes ever lead to lower-lever rules?

I believe the answers to all these questions is no.  Processes are processes, and rules are rules.  They are not the same.  A fundamental principle of the business rule approach is that each is a primitive.  Formally, one primitive can never decompose to another primitive.  So processes never decompose into rules, and rules never decompose into processes, at least within the horizon of interest to the business problem.  (What happens at the implementation level may be a different matter, but that's a platform issue.)

Aside:  Higher-level business logic (e.g., policies) does usually need to be translated into more atomic rules, but this analytical process follows different patterns and guidelines than for recursive decomposition of processes.  We therefore use the term reduction (instead of decomposition) for transforming high-level business logic to lower-level form.

An implication of this view is that it is never really accurate to say that policies and rules are innately inside processes.  (You might "find" them there, but that is an artifact of presentation or methodology -- not something inevitable in the natural scheme of things.)  CEOs set policies, then managers create business processes.  Or consultants create business processes, and managers establish policies and rules.  This can happen in either order (or at the same time), but the processes nonetheless remain processes and the rules remain rules.

Consider the playbooks and the rulebook of the National Football League.  Do you see the rules in the playbooks, or the plays (processes) in the rulebook?  No.  Each stands on its own.  Works out very well that way too, I might add!

All bets are off on these questions, of course, if you cross over into a new perspective (row in Zachman terms).  For example, in creating a technical design at the class-of-platform perspective (row 4), you might decide to treat a rule as a process (or vice versa), but that's are entirely different matter.  That's a design decision -- not something innately true about rules and processes.  And by the way, given the power of rule engines these days, it's not even a particularly good design decision!

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Standard citation for this article:

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Ronald G. Ross, "Do Rules Decompose to Processes or Vice Versa?" Business Rules Journal, Vol. 4, No. 12, (Dec. 2003)

About our Contributor:

Ronald  G. Ross
Ronald G. Ross Co-Founder & Principal, Business Rule Solutions, LLC , Executive Editor, Business Rules Journal and Co-Chair, Building Business Capability (BBC)

Ronald G. Ross is Principal and Co-Founder of Business Rule Solutions, LLC, where he actively develops and applies the BRS Methodology including RuleSpeak®, DecisionSpeak and TableSpeak.

Ron is recognized internationally as the "father of business rules." He is the author of ten professional books including the groundbreaking first book on business rules The Business Rule Book in 1994. His newest are:

Ron serves as Executive Editor of and its flagship publication, Business Rules Journal. He is a sought-after speaker at conferences world-wide. More than 50,000 people have heard him speak; many more have attended his seminars and read his books.

Ron has served as Chair of the annual International Business Rules & Decisions Forum conference since 1997, now part of the Building Business Capability (BBC) conference where he serves as Co-Chair. He was a charter member of the Business Rules Group (BRG) in the 1980s, and an editor of its Business Motivation Model (BMM) standard and the Business Rules Manifesto. He is active in OMG standards development, with core involvement in SBVR.

Ron holds a BA from Rice University and an MS in information science from Illinois Institute of Technology. Find Ron's blog on For more information about Ron visit Tweets: @Ronald_G_Ross

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