About this series of articles

While my first series of articles on writing natural language rule statements^[1] explored a wide variety of issues in a rather organic and hence random manner, this series takes a more holistic and systematic approach and draws on insights gained while writing my recently-published book on the same topic.^[2]  Rule statements recommended in these articles are intended to comply with the Object Management Group's Semantics of Business Vocabulary and Business Rules (SBVR) version 1.0.^[3]

The story so far

In previous articles in this series (see the "Language Archives" sidebar) we have looked at standardised rule statements for various types of data rules^[4] and activity rules.^[5]  Each specific type of rule statement has a common formulation which we have discussed in both a relatively informal way and by way of rule statement patterns.

In this article, we will be looking at another type of rule, the party rule.^[6]

Party rules:  an overview

Each rule that we have encountered so far applies to all parties who are subject to that rule.  I recall as a small boy being told by a person in authority "I don't care if you're the Queen of England, you still can't."  For example, anyone can fill in a flight booking request and confirmation online provided they have a credit card or can make an electronic payment; any person can pass through an entry barrier at a train station if that person presents a current ticket valid for travel from that station, on that day, and at that time.

However, some rules stipulate which parties (individuals or organizations) or roles are allowed to perform a business process or use information.  These rules are rarely in terms of specific individuals, being more often in terms of roles that may be played by parties (e.g., Captain, First Officer, Flight Attendant).  Other rules, however, may refer to organizations, either specific departments within the business (e.g., the Purchasing Department) or specific external organizations (businesses or government departments).

Restrictions on who can perform an activity or play a role may be based on age, for example:

1. A person who is less than 5 years of age is prohibited from travelling alone by air.


2. A person who is 70 years of age or older is prohibited from obtaining travel insurance with some (if not all) insurance companies.

Alternatively, a restriction may be based on some other physical characteristic or capability, for example:

1. A cabin crew member^[7] must be at least 160cm (5'3") tall.


2. A passenger who is unable to open an aircraft door in an emergency is prohibited from being allocated to a seat in an exit row.

For an activity requiring particular skills and/or involving physical or financial risks, a person may only perform that activity if that person has been certified as having been appropriately trained, tested, and certified in the appropriate skills, for example:

1. A person who does not hold a current commercial pilot licence is prohibited from being rostered on a flight crew.


2. A person is also prohibited from being rostered on a flight crew if that person does not hold type endorsements appropriate to all aircraft types to be flown by that flight crew.


3. A person who does not hold a current command endorsement is prohibited from being rostered as pilot in command on a flight crew.

It should be clear that compliance or non-compliance with each of these rules depends on who is being proposed for the process or activity.  For example, I can obtain travel insurance since I am less than 70 years of age, and be allocated to an exit row seat since I can open an aircraft door in an emergency, while my mother can do neither.  Neither of us can be rostered on a flight crew whereas other people are qualified to be so rostered.

Some situations require separation of responsibilities, in that the same person (or organisation) is prohibited from performing two activities.  For example, the activities of disarming an aircraft door and checking that that door is disarmed must not be performed by the same cabin crew member.^[8]

Still other situations require that the person (or organisation) performing the second of two activities must be the same as the person (or organisation) who performed the first of those activities.  For example, the flight crew member who signs the pre-flight check report must be the same flight crew member who performed the pre-flight check documented in that pre-flight check report.

Finally, there are rules which define the responsibility of particular parties or roles for performing certain processes or paying certain fees, duties, or taxes.

Types of party rule

Party rules can be categorised as:

1. party restriction rules, which place restrictions on who can perform some processes or activities or play some roles, based on age, some other physical characteristic or capability, or training, testing, and certification in the appropriate skills, for example:

2. role separation rules, which prohibit the same party from performing two activities, for example:

3. role binding rules, which require that the party performing the second of two activities must be the same as the party who performed the first of those activities, for example:

4. information access rules, which define who can view, create or update particular information, for example:

5. responsibility rules, which define who is responsible for performing a particular process or liable for a particular fee, duty or tax, for example:

Rule statement patterns for party rules

In the following patterns:

1. <party term> is person, organisation, or some term signifying the role that is in some way subject to the restriction, e.g., passenger.


2. <activity verb> signifies the activity subject to the restriction.


3. <information term> signifies the information that is subject to the restriction, e.g., leave records.


4. <responsibility term> signifies the process, fee, duty or tax for which the responsibility is nominated, e.g., final quality review, stamp duty.


5. <responsibility verb> signifies the responsibility placed on the party that is responsible.

Note that these patterns (and the others that have been described in previous articles in this series) involve various syntactic components that are yet to be defined in detail:

1. <qualifying clause>, e.g.,


• in an exit row


• who checks that an aircraft door is disarmed


• who disarmed that aircraft door


• who performs the quality review of a project deliverable


• who updated that project deliverable


• who signs the pre-flight check report


• who performed the pre-flight check documented in that pre-flight check report


• who signs the quality review report


• who performed the quality review documented in that quality review report


• on a real property transfer


• of each project deliverable


2. <noun phrase>, e.g.,


• a seat in an exit row


• a cabin crew member


• a flight crew


• the pilot in command on a flight crew


3. <conditional clause>, e.g.,


• the age of that person is at least 5 years


• that passenger is able to open an aircraft door


• the height of that person is at least 160cm


• that person holds an airline transport pilot license
      that is current
  and a type endorsement
      that is current for each aircraft type to be flown by that flight crew


• the current medical status of that person is A1


• that person holds a command endorsement
      that is current


4. <party list>, e.g.,


• that employee,
      the supervisor of that employee,
      or a human resources officer


• the parties receiving


• the quality assurance officer

All of these syntactic components will be defined in detail in a future article in this series.

To be continued...
The next article in this series will look at definitional rules.^[10]

References

[1]  The first of which is:  Graham Witt, "A Practical Method of Developing Natural Language Rule Statements (Part 1)," Business Rules Journal, Vol.  10, No.  2 (Feb.  2009), URL:  http://www.BRCommunity.com/a2009/b461.html  

[2]  Graham Witt, Writing Effective Business Rules.  Morgan Kaufmann (2012).  

[3]  Semantics of Business Vocabulary and Business Rules (SBVR), v1.0.  Object Management Group (Jan.  2008).  Available at http://www.omg.org/spec/SBVR/1.0/
     The font and colour conventions used in these rule statements reflect those in the SBVR, namely underlined teal for terms, italic blue for verb phrases, orange for keywords, and double-underlined green for names and other literals.  Note that, for clarity, these conventions are not used for rule statements that exhibit one or more non-recommended characteristics.  

[4]  A rule that constrains the data included in a transaction (a form or message) or a persistent data set (e.g., a database record).  

[5]  A rule that constrains the operation of one or more business processes or other activities.  

[6]  A rule that makes a distinction between different parties or the roles they play.  

[7]  'Cabin crew member' is the generally preferred term in the airline industry for persons previously known as 'flight attendants'.  

[8]  'Arming' of aircraft doors after closure but before take-off ensures that, if a door is opened after a crash or emergency landing, an escape slide automatically inflates. On landing, of course, all doors must be disarmed.  

[9]  A tax levied by Australian states on parties undertaking real property (real estate) transactions.  

[10]  A rule that constrains how an organization (or the industry within which it operates) defines a construct created or used by that organization or industry (and which therefore cannot be contravened), as distinct from an operative rule, which states what must or must not happen in particular circumstances (and which therefore can be contravened); all rules encountered so far in this series have been operative rules.  

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