Conway’s Law: Critical for Efficient Team Design in Tech - IT Revolution


This post on Conway’s Law is adapted from Chapter 2 of Team Topologies: Organizing Business and Technology Teams for Fast Flow.

Conway’s Law

Conway’s law is critical to understanding the forces at play when organizing teams amidst the long-lasting, unattended impact they can have on our software systems, as the latter have become larger and more interconnected than ever before. But you might wonder if a law from 1968 about software architecture has stood the test of time.

We’ve come a long way after all: microservices, the cloud, containers, serverless. Such novelties can help teams improve locally, but the larger the organization, the harder it becomes to reap the full benefits. The way teams are set up and interact is often based on past projects and/or legacy technologies (reflecting the latest org-chart design, which might be years old, if not decades).

This quote from Ruth Malan provides what could be seen as the modern version of Conway’s law: “If the architecture of the system and the architecture of the organization are at odds, the architecture of the organization wins.”

Malan reminds us that the organization is constrained to produce designs that match or mimic the real, on-the-ground communication structure of the organization. This has significant strategic implications for any organization designing and building software systems, whether in-house or via suppliers.

In particular, an organization that is arranged in functional silos (where teams specialize in a particular function, such as QA, DBA, or security) is unlikely to ever produce software systems that are well-architected for end-to-end flow. Similarly, an organization that is arranged primarily around sales channels for different geographic regions unlikely to produce effective software architecture that provides multiple different software services to all global regions.

Communication paths (along formal reporting lines or not) within an organization effectively restrict the kinds of solutions that the organization can devise. But we can use this to our strategic advantage. If we want to discourage certain kinds of designs—perhaps those that are too focused on technical internals—we can reshape the organization to avoid this.

Similarly, if we want our organization to discover and adopt certain designs—perhaps those more amenable to flow—then we can reshape the organization to help make that happen. There is, of course, no guarantee that the organization will find and use the designs we want, but at least by shaping the communication paths, we are making it more likely.

Organization design using Conway’s law becomes a key strategic activity that can greatly accelerate the discovery of effective software designs and help avoid those less effective.

Software Architectures that Encourage Team-Scoped Flow (The Reverse Conway Maneuver)

To increase an organization’s chances of building effective software systems optimized for flow, a reverse Conway maneuver (or inverse Conway maneuver) can be undertaken to reconfigure the team intercommunications before the software is finished. Although you might get initial pushback, with sufficient willpower from management and awareness from teams this approach can and does work.

Conway’s law tells us that we need to understand what software architecture is needed before we organize our teams, otherwise the communication paths and incentives in the organization will end up dictating the software architecture. As Michael Nygard says: “Team assignments are the first draft of the architecture.”

For a safe, rapid flow of changes, we need to consider team-scoped flow and design the software architecture to fit it. The fundamental means of delivery is the team, so the system architecture needs to enable and encourage fast flow within each team. Thankfully, in practice, this means that we can follow proven software-architecture good practices:

  • Loose coupling—components do not hold strong dependencies on other components.
  • High cohesion—components have clearly bounded responsibilities, and their internal elements are strongly related.
  • Clear and appropriate version compatibility.
  • Clear and appropriate cross-team testing.
  • At a conceptual level, software architectures should resemble the flows of change they enable; instead of a series of interconnected components, we should be designing flows on top of an underlying platform.

By keeping things team sized, we help to achieve what MacCormack and colleagues call “an ‘architecture for participation’ that promotes ease of understanding by limiting module size, and ease of contribution by minimizing the propagation of design changes.” In other words, we need a team-first software architecture that maximizes people’s ability to work with it.

Organization Design Requires Technical Expertise

How much awareness does the HR department have about software systems? Does the group of department leaders deciding how to allocate budget across teams know of the likely effects of their choices on the viability of the software architecture?

Given that there is increasing evidence for the homomorphism behind Conway’s law, it is very ineffective (perhaps irresponsible) for organizations that build software systems to decide on the shape, responsibilities, and boundaries of teams without input from technical leaders.

Organization design and software design are, in practice, two sides of the same coin, and both need to be undertaken by the same informed group of people.

Fundamentally, we need to involve technical people in organization design because they understand key software design concepts, such as APIs and interfaces, abstraction, encapsulation, and so on. Naomi Stanford puts it like this: “departments and divisions, systems, and business processes . . . can be designed independently as long as interfaces and boundaries with the wider organization form part of the design.”

Conway’s law tells us that an organization’s structure and the actual communication paths between teams persevere in the resulting architecture of the systems built. They void the attempts of designing software as a separate activity from the design of the teams themselves.

The effects of this simple law are far reaching. On one hand, the organization’s design limits the number of possible solutions for a given system’s architecture. On the other hand, the speed of software delivery is strongly affected by how many team dependencies the organization design instills.

Fast flow requires restricting communication between teams. Team collaboration is important for gray areas of development, where discovery and expertise is needed to make progress. But in areas where execution prevails—not discovery—communication becomes an unnecessary overhead.

One key approach to achieving the software architecture (and associated benefits like speed of delivery or time to recover from failure) is to design teams to match the desired architecture.

In short, by considering the impact of Conway’s law when designing software architectures and/or reorganizing team structures, you will be able to take advantage of the isomorphic force at play, which converges the software architecture and the team design.

"An organization that is arranged in functional silos (where teams specialize in a particular function, such as QA, DBA, or security) is unlikely to ever produce software systems that are well-architected for end-to-end flow." Click To Tweet