Single-threaded leadership is the most critical organizational design concept at Amazon. It has been instrumental in avoiding coupling and slow velocity while increasing the number of initiatives that Amazon can run in parallel.

The basic idea behind single-threaded leadership is that for each initiative or business problem, there is a leader whose focus is that initiative and that initiative alone. That person leads one or more separable, single-threaded teams to deliver the initiative goals. The name comes from computer science terminology—a single-threaded program executes one command at a time.

Single-threaded leaders are owners

Many companies find themselves struggling against their own bureaucratic drag, which appears in the form of layer upon layer of permission, ownership, and accountability, all working against fast, decisive forward progress.

Colin Bryar and Bill Carr, Vice Presidents at Amazon

In many companies, critical initiatives languish because of the lack of a clear mandate. No one is empowered to make it happen end to end. The single-threaded model is a change of mindset regarding ownership—all success and failures rest with the leader, and the bucket stops there.

A single-threaded leader is an individual wholly dedicated to solving one business problem, someone who wakes up in the morning and worries just about that one thing, ensuring the initiative’s vision and goals are always at the forefront and is ready to escalate risks early.

Single-threaded leaders may be individual contributors, manage a single-threaded team, or a large organization whose attention is similarly focused on that one initiative. The defining characteristic is not the scope of the initiative but the single-threaded nature of the work.

The best way to fail at inventing something is by making it somebody’s part-time job

David Limp, Senior Vice President of Devices and Service at Amazon

The single-threaded model at Amazon manifests in two variants – Single-Threaded Ownership (STO) and Single-Threaded Leadership (STL). In both models, the leader is responsible and accountable for delivering results for only one thing, but the organization structure differs.

In the single-threaded ownership model, the leader controls all resources required to deliver on the initiative. In this model, reporting structures align with project responsibilities, and each team member reports directly to the leader.

In the single-threaded leadership model, the leader recognizes that maintaining reporting lines within functional disciplines is helpful (e.g., engineers report to engineers, designers to designers), meaning team members benefit from functional leadership and natural career development. The single-threaded leader works across disciplines to drive prioritization and roadmaps and manages all of the associated cross-team communication but does not ultimately control the resources required for delivery.

The single-threaded ownership model is more effective for ongoing product work requiring end-to-end ownership of all dependencies, such as launching complex new programs like Amazon’s Fulfilment by Amazon. The single-threaded leadership drives essential work across the company, such as the famous API mandate by Jeff Bezos or addressing GDPR requirements that affected a large number of teams.

Finally, not all teams and initiatives need to be single-threaded. Some teams, by their nature, make more sense organized functionally, for example, legal, sales, or finance. As with any other organizational design concept understanding the benefits and trade-offs is essential to apply successfully.

Single-threaded teams are separable and autonomous

Separable means almost as separable organizationally as APIs are for software. Single-threaded means they don’t work on anything else.

Jeff Wilke, Ex-CEO of Amazon's worldwide consumer business

Over the years, I have learned that the most critical element in determining team success is autonomy—the ability of a team to decide how to best fulfill its mission and deliver its roadmap independently. Single-threaded organizations structure in ways that allow teams to complete their tasks without blocking others, waiting for others, or aligning decisions with others. Teams significantly reduce the time and energy spent in coordination if they can accomplish their goals without communicating with the rest of the organization. Therefore, teams must have all required roles to fulfill their goal, including software engineering, quality assurance, customer experience design, and product management.

A single-threaded team with a dependency owns driving the process to de-couple it. Dependencies delay results, increase frustration and disempower teams. Appointing a single-threaded leader is necessary but not sufficient. Equally critical to the single-threaded model is that teams untangled their dependencies. To succeed, single-threaded teams need to have the minimum possible number of organizational and technical dependencies even if the cost of separating the dependency is duplication.

The most successful teams invested much of their early time in removing dependencies and building “instrumentation”—our term for infrastructure used to measure every important action—before they began to innovate, meaning, add new features.

Bill Car, Vice President of Digital Media at Amazon

In organizations where every decision is reviewed at multiple levels, there is little incentive to think deeply about a problem, and teams will rely on managers as safety gates, reducing the team ownership of the product. Furthermore, since the team is directly connected to the outcome of their decisions, it creates a powerful feedback loop, improving the team’s decision-making skills.

Single-threaded model tenets (unless you know better ones)

At Amazon, we used tenets to codify how we think about specific things, a set of principles that act as a north star for establishing and operating as single-threaded leaders.

1. Focus - The single-threaded leader should be the most effective decision-maker for the business area, irrespective of title or functional role
2. Responsibility - Single-threaded leaders are empowered to make their own decisions even if these turn out to be bad decisions in hindsight
3. Accountability Single-threaded leaders own their dependencies and are responsible and accountable for all aspects of the initiative for the success of the initiative
4. Empowerment - Single-threaded teams are accountable for holding a high-quality bar for customers and should continue to follow good governance practices. Unless an explicit exception, the single-threaded leader cannot override existing good governance practices
5. Decision making - The single-threaded leader acts as a tie-breaker if the team cannot agree on a decision

We disproportionally index in hiring builders, and then we organize them in small separable and autonomous teams as we possibly can and let them own their own destiny

Andy Jassy, CEO of Amazon

Hear directly from Colin Bryar, Vice President at Amazon

Questions to consider

Before establishing a single-threaded leader, ask some questions:

• If this is a critical initiative, is there a leader whose focus is the initiative and that initiative alone? Is the leader empowered to lead it? Is the leader solid and capable of succeeding?
• Do you manage dependencies in a forthright manner to improve the odds of success?
• Does the organization have a plan to untangle dependencies so teams can work independently?
• What is the bounded context that defines the scope of ownership of the single-threader leader?
• Can teams build and roll out their changes without coupling, coordination, and getting approvals from other teams?
• How does the single-threaded model change your existing review process?
• How does the single-threaded model improve decision-making? Can a single-threaded leader simplify and accelerate the decision-making process?

In Conclusion

Being free from distractions and competing priorities helps leaders focus on owning end-to-end separate “start-ups” within the organization, allowing companies to drive multiple initiatives forward in parallel without complex bureaucracy. The single-threaded model helps leaders devote time to making decisions about their goals rather than chasing approval from higher-ups.

Organizing in separable single-threaded teams allows companies to decide the best way to own and untangle their dependencies and reduce the need for coordination with the rest of the organization. It might create duplication, but builders are willing to exchange that for moving fast.

Organize builders into teams that are as separable and autonomous as possible: It’s hard for teams to be deep in what customers care about in multiple areas. It’s also hard to spend enough time on the new initiatives when there’s resource contention with the more mature businesses; the surer bets usually win out. Single-threaded teams will know their customers’ needs better, spend all their waking work hours inventing for them, and develop context and tempo to keep iterating quickly.

Andy Jassy, CEO of Amazon. Letter to Shareholders 2021

The single-threade model is a mechanism to deliver initiatives at scale. Start-ups and small business might not have enough senior leadership resourcers to fully dedicate them in this manner. Despite this, any size company can learn from establishing clear end-to-end ownership and focus on decision-making speed.

In future posts, I will dive deeper into how to implement single-threaded teams and the necessary mechanisms to do it successfully. In the meantime, feel free to reach out via LinkedIn or Twitter