Independent Service Heuristics (ISH) is a set of questions teams can use to find where to set team and software boundaries that will enable Fast Flow of value. This technique was invented by the authors of Team Topologies, Matthew Skelton and Manuel Pais, and subsequently refined by other members of the wider Domain Driven Design community.
You'll find more information via the Independent Service Heuristics GitHub Repository which is openly provided via the CC BY-SA license.
Choosing an area of focus
This practice helps teams to get started and avoid analysis paralysis by using a series of questions to help identify where to focus attention, or quickly decide an area of focus is not suitable for further discovery after all.
"When designing organizations for fast flow of change, we need to find effective boundaries between different streams of change… The ISH approach covers many typical situations in modern software but not all. It's designed to stimulate conversation and provide a frame for thinking, not as a perfect "catch-all" tool."
ISH is a good way to enable people with a range of skills and backgrounds to have meaningful conversations, and create alignment across organisational boundaries.
Start by asking “Could this thing be run as a cloud-hosted (SaaS) service or product?”
Could it make any logical sense to offer this thing "as a service"?
Could you imagine this thing branded as a public cloud service (like AvocadoOnline.com 🥑)?
Could this thing be managed as a viable cloud service in terms of revenue and customers?
Could the organisation currently track costs and investment in this thing separately from similar things?
Is it possible to define clearly the input data (from other sources) that this thing needs?
Could this thing have a small/well-defined set of user types or customers (user personas)?
Could a team or set of teams effectively build and operate a service based on this thing?
Would this team be able to act independently of other teams for the majority of the time to achieve their objectives?
Would the scope of this thing provide a team with an impactful and engaging challenge?
Would the team working on this thing be able to "own" their own product roadmap and the product direction?
Answer these questions for each of the candidate streams you have identified. The more 'yes' or 'maybe' answers a possible stream has, the greater the chance that you have found a good candidate for being a separate stream of change.
Check out these great links which can help you dive a little deeper into running the Independent Service Heuristics (ISH) practice with your team, customers or stakeholders.