Your ability to respond in appropriate ways to pinpoint circumstances where business rules are breached – automatically and independently of processes – provides the mechanism you need to support very smart, very friendly business systems. Normally we think about breaches occurring for behavioral rules, where a breach means a violation has occurred. Can breaches occur for decision rules too? The answer is yes and no. Read on!
A breach occurs for a business rule when the business rule isn’t satisfied upon being applied to some set of circumstances (state of affairs). Normally we think about breaches occurring for behavioral rules, where a breach means a violation has occurred (e.g., you violated the posted speed limit).
The potential for violations of behavioral rules raises several important questions that business analysts should answer in advance of deployment for each behavioral rule:
1. What level of enforcement should be applied.
2. What special response to a violation is appropriate, if any.
3. What special message, if any, should be returned to some worker(s) upon a violation.
Unlike behavioral rules, no definitional rule can ever be violated. Literally, things must be correct under such rules by definition.
Let’s take an example. Suppose somebody asserts “2+2=5”. According to the rules of mathematics, we know the correct answer is 4. The answer “5” is deemed irrevocably wrong. But is the asserted answer ever allowed to stand?
If the rule is defined as a decision rule, the asserted answer is never allowed to stand. More precisely, the assertion would never be recognized to have happened in the first place. If someone asserts “2+2” the answer “4” is concluded immediately. Period. No breach, no opportunity for error.
If defined as a behavioral rule (one that is not strictly enforced), the asserted answer is allowed to stand, but a violation is recognized. How might that capability be useful? Suppose the error were made by a student in grade school. It might be quite useful for the student and/or a tutor to know about it immediately and automatically. Specifying an appropriate violation response can make such notification happen.
In business, of course, definitional rules can be far more complex. Nonetheless, your ability to respond in appropriate ways to the pinpoint circumstances where certain rule-related events occur – automatically and independently of processes – provides exactly the mechanism you need to support very smart, very friendly operational business decision systems.
Decision Rules and Breaches
Decision rules are a special kind of definitional rule involving implications (e.g., A implies B). They support inferences and determinations – identifying an appropriate outcome from among a set of alternatives.
Like all decision rules, definitional rules cannot be violated. They are simply deemed true by definition.
Purely from a business perspective, however, some assertions of fact(s) may make it appear that a breach-like event has occurred. I take pains to emphasize any such perception is purely from the business perspective, not from the perspective of logic. You perceive a breach of a decision rule simply because it’s useful to do so, not because any true violation has occurred.
In evaluating some particular case (situation, set of circumstances, or matter of concern), for example, things might not follow the ‘happy path’. Think of a breach of a decision rule as a bump in the road – a gap along the happy path.
Let’s return to the three questions listed earlier. Although the first question about enforcement level obviously doesn’t apply to decision rules, adjusted versions of questions 2 and 3 remain in play.
Consider the following simple business example. Suppose a bank has this decision rule:
A credit application must be considered discrepancy-free with respect to a credit report for the applicant if all the following are the same:
date of birth
Social Security Number
Let’s suppose that an applicant uses just the initial for her middle name on her credit application. If the credit report shows her full middle name, then the names are not the same and the credit application will not be considered discrepancy-free.
Note carefully the rule hasn’t been violated; it did its ‘work’ correctly and it did reach the proper conclusion (not discrepancy-free). But a gap – a breach – for her case has been identified from a business perspective because the rule failed on one of the conditions. We should be able to take advantage of that breach to take appropriate action – selectively, automatically and in real time.
For example, the desired response to the breach might be to insert the following to-do item in the work queue of the responsible staff member: “Review discrepancy and manually ok if appropriate”. (The to-do item should naturally also provide ready access to the related documents.) The breach of the rule causes this action to occur automatically.
Think about how many decision rules might exist for determining credit-worthiness, and how many selective conditions they might have. Could you build a responsive system by incorporating the selective responses needed into the related process model(s)? Not a chance – that approach won’t scale. Instead, the selective responses need to be specified based on the business-rule side of things.
Kinds of Breach Specifications for Decision Rules
Breach specifications for a decision rule can be of the following two kinds.Breach Response. A breach response can be an action of virtually any kind. For example, a breach action might be to:
Add some task(s) to a (non-redundant) to-do list in some appropriate work queue.
Add some documentation items to a (non-redundant) not-yet-received list.
By these means very selective follow-up processing/handling (“what to do next”) can be organized pertaining to any specific issue (breach) for a given case. Such selectivity is made possible by the granularity of the rules.
Breach Message. A specially-worded breach message can be forwarded to any involved party either inside or outside the company. A breach message generally explains one or both of the following at any level of detail desired:
Why the rule or condition failed. (The rule or condition statement already indicates very precisely what the issue is, but the breach message can explain in a more friendly manner.)
What should be done to address the issue.
More Complex Example
Breach specifications apply selectively and specifically to a decision rule and/or any of its conditions. A breach specification applies if and only if that decision rule and/or condition fails (is not true) in evaluating some specific case (e.g., a specific credit application). An example of a decision rule with condition-specific breach specifications is illustrated in Table 1.
Table 1. Example of More Complex Decision Rule with Condition-Specific Breach Specifications
A fluctuating income must be considered eligible if all the following are true:
Conditions of the
the applicant has a 3-year proven track record of consistent income
the applicant is likely to have comparable income in the future
Add to-do item for that credit application: “Contact employer to verify applicant has reasonable opportunity for future income.”
the income is validated
Add required documentation items not yet received to a pending list for the credit application.
To applicant: “[date] Here’s a list of documentation items related to your income we have not yet received. [pending list].”
Using Breach Specifications
Breach specifications can be:
General for an entire decision rule including all its conditions. (The example in Table 1 doesn’t include any whole-rule specifications. If the rule did they would appear in the first row.)
Specific to a given condition.
Specific to collections of conditions (none shown for the example).
A breach is detected only if the conclusion of the rule as a whole, or some particular condition within it, evaluates to not true. Things being true should be viewed as moving the case along the desired path (i.e., no breach has occurred). Decision rules (and breach specifications) should be expressed carefully so as to preserve this positive orientation.
Generally, breach actions should be specified only if something can be done to overcome a failure (of a rule or condition). The goal is to move things forward in the case. In the example above, for instance, if nothing whatsoever can be done to correct an issue, the credit application should simply be declined. A behavioral rule to that effect should be specified.
In hierarchies of decisions (e.g., as in Q-Charts) and decision rules (e.g., as based on series of logical dependencies), breach specifications should generally be made only at the lowest level of rule reduction/decomposition. A rule at a higher level in a logical hierarchy only evaluates to not true if some rule(s) below it evaluate to not true. Define breach specifications at the lowest level of granularity.
Although rules can be specified in violation specifications for behavioral rules (e.g., to express some sanction or penalty), they should never be specified within breach specifications for a decision rule. Such ‘nesting’ of rules, especially on the basis of ‘not true’, is inappropriate.
Otherwise the advantages of overall declarative specification can be forfeited.
By default, breach specifications for a decision rule apply only the first time it is evaluated for each case. The assumption is that all business rules, including decision rules, are evaluated on a continuous basis. Re-application of any breach specification for a case therefore requires additional timing and iteration criteria. Whether a case is evaluated iteratively on the same set of decision rules based on timing criteria applied by or for some external process or platform is outside the scope of this discussion. No matter what the scheme of evaluation, the expression of the decision rules – as for all business rules – should be completely unaware of it.
Behavioral Rule: A student with a failing grade must not be an active member of a sports team.
This business rule:
Is not about selecting the most appropriate sports team for a student – i.e., not about the decision, Which sport team is best for a student?.
Does not apply only at a single point of determination – e.g., when a student joins a team.
Instead, the business rule is meant to be enforced continuously – for example, if a student who is already active on some sports team should let his or her grades fall. What’s the business decision for when a student’s grades fall and they should be taken off a team? Be real, there’s no good answer to that question.
This example is no outlier. Businesses have 1,000s of behavioral rules like this.
Let’s be clear – I believe a business-decision-based approach is very powerful for decision rules. I have written much about that. And I don’t disagree that many business-rule projects have floundered due to lack of pragmatic organizing principles (e.g., “decisions”).
But if you take a decision approach to behavioral business rules, either it will prove woefully incomplete with respect to integrity, or you’ll quickly start to drown in (system-level) decisions.
In my opinion, an application that has to be designed and to operate to treat violations of behavioral rules as just more decisions is not a smart enough system.
The detection of violation events for behavioral rules can be, and should be, completely under the covers (identified, detected and supported by a platform). Otherwise the solution won’t scale. And there will be so many decision dependencies it will steal from the very real value of a business-decision-based approach.
This frankly is a sign of immaturity … or lack of imaginative leadership … or IT bias … or whatever … in some parts of the decision-model community. The detection of a violation of a behavioral rule is an event, not a decision. A business decision is a business decision; a system decision is … well … why even go there?!P.S.There are 3 specific examples and more complete discussion about this topic on http://goo.gl/NCnLi.
In classifying ‘rules’ I go by the standards … Business Motivation Model (BMM): business policies vs. business rules
Business rules are always practicable – workers can apply them directly.
Business policies are not – they must be interpreted first.
SBVR: definitional rules (necessities) vs. behavioral rules (obligations) vs. advices (possibilities or permissions).
Definitional rules (including decision rules) are about shaping knowledge (and cannot be violated).
Behavioral rules are about shaping conduct (and can be violated).
Advices are non-rules; they provide practicable guidance but do not remove any degree of freedom.
I would add only these observations:
The kinds of rules you see in decision tables are generally definitional. Since they represent only a subset of all definitional rules I call them ‘decision rules’ for convenience.
Condition-Action or Event-Condition-Action (ECA) rules are not business rules at all. They are representations of business rules (for a class of implementation platforms).
My smart phone can tell me in spoken English where the nearest gas station is. It’s only a matter of time before machines start ‘reading’ regulations, contracts, agreements, business policies, etc. to help people formulate (through dialog) practicable (and implementable) business rules. Can you imagine the productivity benefits?!
Decision tables are great. Everybody should use them. But they are a lot harder to design well than you might think.
The DMN standard can move things along significantly … if it is good, and it isn’t overhyped (which it already has been in certain quarters). I’m looking forward to it impatiently. But standardization (in equal parts a political process and a technical process) do take some time!
“The relation between business rules and decisions is I think pretty well agreed by all – it’s just that some focus on 1 or the other, and some both – any “disagreement” is more on the value in the different approaches.”
I respectfully disagree (strongly). There are fundamental differences between decision rules and behavioral rules including these:
1. Behavioral rules are usually one of a kind. They don’t fit in decision tables. Some might appear in decision models if you are concerned about such things as integrity (will the DMN standard be?), but the large majority don’t.
2. Decisions are generally single point of determination for any given real-world case. Most behavioral rules are multi point of determination, meaning they could be violated under quite different circumstances.
3. The detection of violations of behavioral rules should be automatic and event-based. There’s no “decision” involved in the detection … it should be automatic. (This is where the current generation of rule engines … mostly based on 1980s expert-system thinking … fall woefully short. It’s also probably one reason they haven’t become more mainstream in industry mindshare.)
4. Behavioral rules generally have a different source than decision rules … laws, regulations, contracts, agreements, deals, certifications, warranties … and business policies. Decision rules sometimes arise from those sources, but if so, have limited coverage. Decision rules in contrast often arise from the heads of knowledge workers and inspection of big data and event streams. (Behavioral rules do too, but likewise don’t begin to cover everything.)
So the issue is by no means simply a “matter of approach”. Spinning it that way might be useful for vendors, but it won’t be helpful to business analysts.
We need to think soberly about the true range of business rules and the fundamental distinctions that exist. If not people will end up very frustrated on the other side of the DMN hype cycle. We can do better than that, and for the sake of the DMN standard, we should.
P.S. For discussion and examples of the fundamental distinction between behavioral rules and decision rules see Appendix 3 in the DecisionSpeak Primer … available for free download on http://www.brsolutions.com/b_ipspeakprimers.php. By the way, DecisionSpeak and its companion TableSpeak are *quite* concerned about integrity in decision models.
written in response to Jacob Feldman:http://www.brsolutions.com/2013/05/07/response-to-decisionspeak-tablespeak-annnouncement/
Jacob, Thanks! And I agree with you about the ‘executable’ part.
Our emphasis is on business-friendly, business-driven models. I believe DecisionSpeak and TableSpeak move things forward significantly in that regard. There’s no reason why decision models have to be oriented to IT development. If they are robust, they will nonetheless be executable.
I would sound a note of caution. Decision models are no silver bullet. There are issues of semantics (vocabulary) and integrity (restrictions) to be addressed.
And they don’t cover even the majority of all business rules – especially behavioral rules. If you throw everything you (should) know about business rules out the window when you use decision models, you will be in for a very rude awaking.
I’m glad we did not rush to the market. We’ve taken our time to do our homework with respect to theory (which has been out there for a great many years) and to hone our approach in real-life consulting work.
I think the results speak for themselves!
guest post by Jan Purchase, Director of Lux Magi Ltd
I do see value in distinguishing ‘policy’ rules from ‘expert’ rules. It’s also clear that, at their extremes, these rule types are poles apart. Still I fear that this distinction may be a continuum rather than a discrete dichotomy.
Policy rules might be exemplified as the constraints of business operational practice – the rules that dictate what a company should and should not do. They might be mined from the boundary conditions of the fact model of the company’s business capability – as you suggest in your excellent book on this subject. An example policy rule might assert, for example, “A company agent may be assigned to a high-value customer only if the agent is assigned to at most five other clients”.
Expert rules, on the other hand, are often seen as more complex – for example, using heuristics to determine the best, anti-cancer drug to apply in a given situation, or forecasting regional sales opportunities. Often these expert rule bases use expert experience, genetic algorithms, fuzzy logic and feedback loops to reach a decision. They seek to augment, or even supplant, the wisdom of a small population of subject matter experts.
But isn’t there a middle ground too? Consider an insurance policy decision rule that bin-sorts clients into good, bad and medium risk (the latter to be referred to a human underwriting expert). If this were a simple four-row, decision table based on the value of the policy and the risk profile of a client, you would probably consider it a ‘policy rule’. But if I add scorecarding, heuristics and analytics, at what point does it become an ‘expert rule’? Would you consider all decision rules (as opposed to constraint rules) to be ‘expert rules’? Or do they need to be complex or directly represent the experience of SMEs?
Don’t all rules, to some extent, represent the wisdom of experts? Don’t many of them constitute and inform policy?
In short: Is there a simple question we can ask (concerning a rule) to determine if it is a ‘policy’ or ‘expert’ rule?
See my reply to Jan:http://www.brsolutions.com/2012/05/29/the-debate-continues-expert-systems-vs-business-rules/Answer to Jan’s Question: The question to ask of every rule is whether the end-point is enforcement or is it a decision. An enforcement rule never becomes a decision rule, and a decision rule never becomes an enforcement rule.Once an enforcement rule, always an enforcement rule (assuming you don’t retire it). You can adjust thresholds (e.g., the mph of the speed limit), you can change the enforcement level (e.g., from ‘strictly enforced’ to ‘override with explanation’), you can change the sanctions (or eliminate them), etc., etc. And you can and should use analytics to measure and improve the rate of success in achieving underlying business goals. But it’s black and white. Enforcement is enforcement and decisions are decisions.
Here is my latest post in the on-going debate over decision management systems, expert systems, and business rules.
There is a fundamental difference between rules whose intent is enforcement (however strict) vs. rules whose intent is to make (expert) decisions.
Rules whose intent is enforcement (e.g., speed limits) revolve around:
* detection of violations (think speed trap)
* level of enforcement (e.g., strictly enforced)
* violation message (electronic sign flashes ‘You’re speeding’)
* violation response (cop chases you down the street with siren)
* sanction or penalty (speeding ticket and a fine)
I chose an example that is probably not automatable (never be too sure) because such ‘behavioral rules’ (SBVR term) are everywhere in everyday life and therefore easy to comprehend independently of existing platforms and IT support. But there are a huge number that are automable; we just seem to be blinded to them sometimes for whatever reason (probably technical bias).
Behavioral rules would not be involved in diagnosing (deciding) what’s wrong with a missle or classifying (deciding) the risk category of a prospect for insurance. In SBVR those are ‘definitional rules’ (or you could call them decision rules). They are about (encoding the know-how to make) smart (expert) decisions.
It is true that decision rules often support behavioral rules in some fashion (e.g., is this particular speeder worth bothering over?). But it always comes down to this fundamental distinction: Is the end-point about enforcement, or is it about a decision. Enforcement and decisions are simply different.
Are decision rules and behavioral rules both business rules? Yes. Should they be treated the same by platforms and methodologies? No. Why? They are different. Failing to understand the difference harms both business ‘users’ (poor governance processes) and decision management systems (oversell).
Consider the following behavioral business rule: A renter must not have possession of more than one rental car.
In discussing enforcement of this rule, one reviewer said something to the effect, “We have to think about what happens ‘at the time of the decision’.
Hold on. What ‘decision’?! I don’t see any decision. What ‘decision’ could he possibly be talking about?
When it comes to behavioral rules and their enforcement, there’s no ‘decision’ in a meaningful business sense. Let’s think it through.
There was the governance decision to create the business rule in the first place, but that’s not operational business activity per se.
There might be a decision about whether and how strictly to enforce the rule, but that is an enforcement question, not an operational business decision either.
If the decision is ‘Are we following our rules?’ that’s a bogus operational business decision. It might be valid as a test or simulation, but that’s not a decision per se either.
A good analogy for the enforcement of behavioral rules is a game of football. There are referees who ‘watch’ on-going (business) activity and throw a flag when a violation occurs. But they stand on the outside of the plays (processes) looking in.
Now a player may ‘decide’ to violate a rule, but we frankly don’t care about individual ‘decisions’ of those kinds. We care only about the resulting (business) behavior (hence behavioral rules).
Let’s return to the behavioral rule: A renter must not have possession of more than one rental car. Here’s the important point with respect to business processes. The rule is expressed declaratively. Although specified only once, it is presumably relevant to multiple business processes – e.g., for new bookings, rescheduling of existing bookings, extension of open rentals, late returns, etc.
We call points in business processes where a rule needs to be tested ‘flash points’. Like the referees in a football game, a run-time business rule facility should be watching all on-going activity to detect violations anywhere and everywhere they might happen. You might say the facility is ‘deciding’ that violations occur, but who cares … again, those are not operational business decisions. For our purposes, violations either happen or they don’t.
Don’t get me wrong. ‘Decisions’ do have an important place in both business rule thinking and in creating smarter business capabilities. But right now there seems to be a whirlpool of decision hype that’s sucking up altogether too many good brain cycles. We need to see what role decisions do play in business analysis clearly so we can exploit the new techniques to their fullest.
What is operational business know-how? How can you model it? What results can you achieve by doing so?
The answers lie with creating true-to-life business models based on behavioral rules, decision rules, operational business decisions, and operational business events — all as first-class citizens. Understanding their intertwined roles is key to creating top-notch business solutions and business operation systems unmatched in their support for business agility and knowledge retention.
Find out what ideas and techniques you need to create know-how models: http://www.brcommunity.com/b623.php
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