Rule Quality ~ The Route to Trustworthy Business Logic

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

Rule Quality

Rule quality refers to the fitness of business rules.  Assessing rule quality falls into two general areas:  validation and verification, as discussed below.  Exciting new opportunities are emerging in this area, especially using automated tools.  Never before has the business been in a position to shape and refine its own guidance and know-how so directly and proactively.

Validation means assessing fitness with respect to business purpose.  The goal is not only to ensure correctness of the rules from the perspective of business people, but also to ensure that when applied, the results will be appropriate in all relevant circumstances.  Validation is largely a matter of diligent analysis, but automated analysis tools can help in many ways.  For example, diagrams can depict logical or computation dependencies between rules; test scenarios can be retained so prior results can be compared with new results for modified rule sets; rules can be analyzed to identify all events where they need to fire to ensure complete coverage; etc.

Verification means assessing fitness with respect to logical consistency.  Verification is always performed on a set of rules, looking for two or more rules that in combination exhibit some anomaly. Below is a quick sampler of common anomalies along with simple examples.

Linguistic Equivalences

  • A permanent employee must receive a salary.
  • An employee who is permanent must receive a salary.

Modal Equivalences

  • An order over $1,000 must not be accepted on credit without a credit check.
  • An order over $1,000 may be accepted on credit only with a credit check.

Logical Equivalences

  • A high-risk customer must not place a rush order.
  • A rush order must not be placed by a high-risk customer.

Subsumations

  • A rush order must have a destination.
  • An order must have a destination.

Conflicts

  • A shipment must include more than 1 order.
  • An out-of-state shipment may include only 1 order.

An additional area of concern in rule quality is completeness -- that is, whether there are gaps or holes in coverage.  As a simple example, consider the clarification:  An order $1,000 or less may be accepted on credit without a credit check.  A missing rule might be:  An order over $1,000 must not be accepted on credit without a credit check.

In practice, rules are often captured by different people at different points in time, so anomalies such as the above can appear even in the best-coordinated efforts.  By the way, such anomalies are not the result of a rule-based approach; rather, they're just a lot easier to spot.

Fortunately, comprehensive detection of such anomalies can be automated.  There are only two caveats in that regard, but they are big ones:

  1. You must coordinate the business vocabulary the rules use.
  2. You want to ensure quality before rules are translated into an implementation language (so business people can better understand them) and/or are used in production (so you don't have to detect anomalies live).

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Standard citation for this article:


citations icon
Ronald G. Ross , "Rule Quality ~ The Route to Trustworthy Business Logic" Business Rules Journal Vol. 6, No. 9, (Sep. 2005)
URL: http://www.brcommunity.com/a2005/b247.html

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 IPSpeak 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 BRCommunity.com 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 http://www.brsolutions.com/category/blog/. For more information about Ron visit www.RonRoss.info. Tweets: @Ronald_G_Ross

Read All Articles by Ronald G. Ross

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