Breaking the myth of single piece flow.

I’ve seen teams grind to a halt in the name of ‘flow’. Work stalls, pressure rises, and people feel like they’re failing to applying Lean. In reality, the system is failing them.

The humble coin flip game allows people to experience the benefit of small batch sizes to the point of single piece flow. I love it. But it's promise is flawed.

It breaks my heart to say it, however, the panacea makes assumptions which are unicorns in the world of software development.

As delivery consultants we're consistently being asked to help organisations achieve faster flow, yet, very rarely do we see the perfect storm of:

1. A stable, dedicated team...

...where each person allocated to that single team, indefinitely. More often we see 'resources' being shuffled around on a frequent basis, based on a senior group making decisions outside of the teams themselves.

Of course, good portfolio management may identify initiatives not delivering value, which may require a strategic pivot. However, these should be infrequent, and where possible involve a full team staying together but picking up a different product backlog.

Context switching is the single biggest cause of waste in organisations today. Check out the research from Gerry Weinberg:

2. The right skills and tools for the job

Having dedicated team members is one thing, but having the right team members is another. Despite the idealism of about having T-shaped people making up cross-functional, self-organising teams, the majority of people bring specific skills to a team.

Finding the balance of skills needed vs. skills present is key, and this also assumes consistency in the nature of work being done.

3. An equal backlog

Whether you breakdown work into smaller pieces using t-shirt sizes, fibonacci, #noestimates, or something else, almost every product backlog contains a wide array of complexity.

Being able to create consistent, predictable single piece flow requires every item to be pretty much the same complexity or effort. Even when this is possible, it takes time to reach this maturity in the structure of the backlog.

4. A consistent, sequential, repeatable process

Pick your framework of choice (Scrum, Kanban, XP, etc), respect it, be disciplined, and trust the process. When clients constantly change the process, skip steps, or find ways around it, then it doesn't serve them as intended.

There should be valid reasons for selecting a framework to begin with, and there should be valid reasons for switching to something different (which should happen infrequently).

Any framework can support single piece flow once it is optimised, which means less focus on the way of working, and more focus on the work.

5. Clear roles and responsibilities

The bigger the org, the more messy this gets, hence the need to articulate, document and socialise who does what & when.

A product team is often required to interact with multiple business stakeholders, software providers, development/delivery partners, change management / PMO and so on. Avoid assuming someone else is taking care of things. Make it explicit.

6. Focus

According to study on interruptions lead Gloria Mark, research from University of California Irvine concluded that when considering knowledge work “it takes an average of 23 minutes and 15 seconds to get back to the task.”

The best way to create focus in your teams is to reduce unnecessary meetings, create agreed break times, and allow them to block time for focussed work.

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Single piece flow can occur when:

• Work items are similar in size and risk.

• Long-standing teams are self-contained and have all the required skills to complete the work end-to-end.

• Bottlenecks in the flow of work are visible and controllable.

Single piece flow is unlikely when:

• Work varies significantly

• Specialist skills are scarce

• External dependencies dominate flow

In conclusion

Should we stop trying to optimise? Do we give up on switching from a project to a product mindset? Are we wasting time on transformation programs?

Of course not.

Small, incremental improvements are always possible. Experiments should be welcomed. Bottlenecks can be removed. Marginal gains compound over time to create big wins.

However, whilst single piece flow is a powerful outcome, it's a poor goal. Focus on stability, clarity, and constraints first. Flow emerges naturally when the system supports it.