Enabling Operational Excellence
Enabling Operational Excellence
Enabling Operational Excellence
Enabling Operational Excellence


We systemize tacit knowledge into explicit knowledge

Blog Enabling Operational Excellence

The DMN definition of ‘decision’ … I don’t think so(!)

A person close to the DMN (Decision Model Notation) standard recently wrote:

In DMN a decision is deliberately defined very broadly … 

“a decision is the act of determining an output value (the chosen option), from a number of input values, using decision logic defining how the output is determined from the inputs”.

My Response I’ve already written that the DMN definition of “decision” seems to be a bit circular. (To know what a “decision” is you need to know what “decision logic” means. But since “decision logic” says “decision”, seems like you need to know what “decision” means.) Let me tell you what else I find wrong with the definition. (All dictionary definitions from MWUD.) Problem 1. MWUD defines “decision” as (1a) the act of deciding. It defines “act” as (1a) a thing done or being done. So which is it? Is a decision a thing “done” or a thing “being done”? In other words, is a decision the result of an action or process, or the performance of an action or process? Big difference! Which does the standard mean? Some clarity would be nice. Problem 2. MWUD defines “decide” as: to dispel doubt on: (a) to arrive at a choice or solution concerning which ends uncertainty or contention *decide what to order for breakfast*  (c) to infer or conclude from available indications and evidence So the real-world definition of “decide” talks about …
  • Arriving at “a choice or solution”.
  • Basing that choice or solution on “indications and evidence”.
Do you see anything in that definition that reduces what is used in making decisions to “inputs” and “outputs”?! That’s ITspeak, not businessSpeak. So let’s not pretend the DMN standard is really about business modeling per se. It’s business reduced to a system view. Problem 3. “Input value” is definitely ITspeak. Fields and attributes in files and databases are what have this kind of “value”. In the business world, people talk about cases, applications (appeals, requests, petitions), communications, situations, circumstances, trends, profiles, and the like. They don’t talk about “input values” to a decision. Get real. Again, the authors of the DMN standard should either be clear it’s really about system stuff … or admit to causing confusion, deliberately or otherwise.

Tags: , , , , , ,

Ronald G. Ross

Ron Ross, Principal and Co-Founder of Business Rules Solutions, LLC, is internationally acknowledged as the “father of business rules.” Recognizing early on the importance of independently managed business rules for business operations and architecture, he has pioneered innovative techniques and standards since the mid-1980s. He wrote the industry’s first book on business rules in 1994.