How should we think about rules from the business perspective?  Definitive and potent answers have recently emerged based on two fundamental categories^[1]:

Structural Rules organize (i.e., structure) basic knowledge of the business, always carrying the sense of logical necessity or impossibility.  A structural rule can be ill-conceived, misunderstood, or misapplied, but it cannot be directly violated.

Operative Rules can be violated directly by people involved in affairs of the business.  Operative rules govern the on-going conduct of business activity, always carrying the sense of obligation or prohibition.

Structural rules tell you what you should or could do; what people actually do is another matter.  Having flesh-and-blood people involved 'in the loop' for knowledge-rich business processes makes a big difference!  Three related best practices in designing business processes with rules and people are the following:

Best Practice 1.  Create separate tasks for creation of special knowledge and for people to take business action.

Do people 'in the loop' need to abide by specific computed or inferred results of structural rules?  If so, specify one or more operative rules.  For example, inference rules may indicate whether or not an applicant for insurance satisfies all prerequisites.  Operative rules indicate whether the decision-maker(s) in the loop must accept a qualified applicant and/or must not accept an unqualified applicant.  The knowledge tasks (e.g., determining the suitability of an applicant) can be based on structural rules; the take-action tasks (e.g., hiring the applicant) can be monitored by operative rules.  Keep them separate.

Best Practice 2.  Consider the cost of rules in developing the business process.

In business terms, it would be very costly (if even possible) to gather all the data that any structural rule in a business process might need.  For example, a car insurance company might have the rule:  An applicant for car insurance is never considered qualified if the applicant is less than the minimum driving age.  Other rules might involve creditworthiness (which could involve an extensive credit check), previous driving history (which could require requesting records from the state), and so on.  If it can be determined right off that the applicant isn't old enough, that's obviously something you want to do.  So a basic goal in designing business processes with rules and people is work avoidance (no pun intended) -- test the cheapest rules first wherever possible.

Best Practice 3.  Separate planned responses to violations of a rule from the process.

The appropriate response to violations of some rule can be given by: 

1. Some other rule(s), which generally prescribe the appropriate sanction(s).
   
2. Some process(es), which generally prescribe(s) the appropriate means of detection/reaction. 

Consider the offside rule in the game of football:  A player must not be offside.  Associated with this rule are both of the following.

1. A rule prescribing the appropriate sanction:  The offside team in a play must be penalized five yards.
   
2. A planned means of detection/reaction:  The line judge watches, blows a whistle, throws a flag, stops the play, etc.

The planned reaction might be an entire business process in its own right, but generally it is not. Instead, it is often assigned as a job responsibility (e.g., for the line judge), especially if not automatable.

For convenience, I have ignored several important things in this brief discussion:  (1) level of enforcement for an operative rule -- how strictly is it enforced, and (2) whether a rule is automatable.  These issues begin to move us toward a system perspective on rules and processes, which I will take up in my next column.

References

[1]  For more, see Chapter 5, Business Rule Concepts: Getting to the Point of Knowledge (Second Edition), by Ronald G. Ross, September 2005.  ISBN 0-941049-06-X - www.BRSolutions.com - These categories are based on:  Semantics of Business Vocabulary and Business Rules (SBVR), by the Business Rules Team, August 2005.  Available to OMG members at www.omg.org as bei/2005-08-01:  BRT's revised submission to the Object Management Group's (OMG) Business Semantics of Business Rules RFP.  For background on the SBVR and the consortium that produced it, refer to "A Brief History of the Business Rule Approach," Business Rules Journal, Vol. 6, No. 1.  Available at www.BRCommunity.com/a2005/b216.html

Excerpted from Chapter 6, Business Rule Concepts:  Getting to the Point of Knowledge (Second Edition), by Ronald G. Ross.  www.BRSolutions.com (September 2005).  ISBN 0-941049-06-X.  Reprinted with permission.

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