Rule Reduction ~ The Route to Atomic Business Rules

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

When rules are first captured, they often embed multiple criteria that need to be broken out as separate rules.  Breaking them out is called rule reduction.  The goal is highly granular or atomic expressions of business guidance that can be independently re-used and modified.

Rule reduction should not be a first-pass activity.  During rule capture, the most important goal is simply to capture as full an understanding of the rule as possible.  Reduction can be done later.

A best practice in rule reduction is never mix criteria for how a computation should be performed in the same rule as do's and don'ts about applying the result.  In other words, avoid intermingling structural and operative criteria in the same rule.  Following this guideline not only enhances clarity with respect to both kinds of criteria, but also improves granularity.

To briefly illustrate both rule reduction and the application of this principle, consider the following computation rule:  The total price of an order item is always computed as the product unit price times its quantity minus 10% if the order is the first order ever placed by the customer.  Rule analysis could should result in the following more granular rules, as explained step-by-step.

Step 1.  To reduce the complexity of rules, always break out computations as separate rules as soon as possible.  For the rule above, this results in the following computation (structural) rule:

The first-time discount is always computed as 10% times the total price of an order item.

Step 2.  Be alert to any more general concept(s) not originally expressed that might also apply.  For example, the first-time discount mentioned in the original rule is perhaps just one of many discounts that sometimes might be applicable to order items.  Express a new (structural) to establish the more general criteria:

The first-time discount is always considered an applicable discount for each order item of the first order that a customer places.

Step 3.  Append the now generalized notion about subtracting applicable discounts into the original (structural) computation rule:

The total price of an order item is always computed as the product unit price times its quantity, minus applicable discounts.

Step 4.  Express any relevant operative rule(s) about how the results of the computation (structural) rule must or must not be used.  This is a rule about the conduct of people, as opposed to the creation of knowledge.  It's the one that can be violated.

The amount charged to customer for an order item must be equal to the total price of that order item.

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Standard citation for this article:

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Ronald G. Ross, "Rule Reduction ~ The Route to Atomic Business Rules" Business Rules Journal, Vol. 6, No. 6, (Jun. 2005)

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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