Calling everything a decision? That does no more good than calling everything ‘thing’!A decision management tool vendor recently wrote:
“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.