The Anatomy of Event Storming

Here at SEP we are continually toying with practices to help us learn from our clients. Learn about their worlds. Learn about their problems. And in this case, learning about their domains.

Event storming is a “cross-discipline conversation between stakeholders with different backgrounds” (from https://www.eventstorming.com/).

Said another way…event storming is an activity that we use as a team (developers, designers, managers) to learn from our clients (sales, marketing, c-level executives) about how their business works. The language that our clients use is typically new to us…I’m a developer and not an expert in things like medical billing, heavy machinery, or credit unions.

Enough about my shortcomings. Let’s talk about the anatomy of an event storming session.

Maybe this is common sense to you. Maybe this is completely foreign to you. For the event storm to be most impactful, we want everyone there…the development/delivery team, the subject matter experts, the users/sponsors, and in my case recently, even the CEO.

As the name event storming suggests, we are focusing on “events”. Events are something that happened in the past. Regardless of whether the event is performed by the system or by a human. We are capturing and expressing explicitly what happens.

By having everyone together talking about these events, we quickly paint a more complete picture of all of the events, the side-effects of those events, and even the rules or policies that must be satisfied for an event to occur.

Optionally, you can begin to capture additional supporting details. Details about the events like the actors, additional systems, key data, and key decisions.

event storming

Anatomy of Event Storming

Some tactical items that have made my event storms successful:

  • Using color, size, or both to differentiate the events from supporting details
  • In general, events should move from left to right
  • Side-effect events can go above or below the events
  • Walking the events both forward and backward, out loud, will undoubtedly help people recall additional events, details, or policies that are worth capturing

Remember to embrace the “storming” in event storming. Have fun with it, have multiple people contributing, mix it up, etc.