Stable Teams Really Do Matter

This content is syndicated from Agile Pain Relief by Mark Levison. To view the original post in full, click here.


impact-smallFor years now Rally has been performing a large ongoing experiment on the Agile world. As a side effect of providing one of the better known tools they’ve managed to see a lot of data accumulate about what makes an effective Agile team. In a report called “The Impact of Agile Quantified” they’ve sanitized the data and then run some statistical analysis on it. 

Here’s what they saw:

  • Dedicating Team Members to one team doubles productivity, reduces variance throughput and leads to a small reduction in defects. They note that this is a fairly common practice among teams.
  • Stable Teams – keeping a team intact for the long term resulted in 60% more productivity; teams were more predictable and responsive.
  • Limiting Work In Progress – reduces defect rates; however, if your WIP limit is already low, reducing it further might affect productivity.
  • Relative/Story Point Estimation[1] – They divide the world into teams that: A – Don’t estimate; B – Estimate Stories in hours; C – Estimate Stories in Points – tasks in hours, and D – teams that only Estimate using Story Points (i.e. teams that have dropped task hours). Their discovery – the teams (A) not using estimates had 2.5 times as many defects as the teams (C) using Story Points and Task hours. An additional surprise – teams (C) using Story Points and task hours had fewer defects than (D) teams only using Story Points. Some of the discoveries in this one could use further investigation.
  • Team Size 7+/- 2 – the findings suggest that teams before the Agile norms are more productive, but have a higher defect rate and reduced predictability, whilst larger teams were more predictable. The authors note that the larger teams typically also used “Story Point Estimation for Stories and Hours for Tasks” – this might explain some of the productivity differences. The authors recommend sticking to the traditional recommendation of 5-9. Before switching all your teams to 3 people or less – which is tempting with the promise of more productivity – also consider the effect on the work if even one team member leaves. This is another datapoint that bears digging into.

I was surprised to find that stable teams are less frequent among the Rally customers than my own. Rally noticed that 1 in 4 people changed every 3 months. Experience at my regular clients suggests that it should be less than that. No matter what the frequency, we have to appreciate that every change is expensive; both in terms of the knowledge lost and the consequent slowdown while team members renegotiate their relationships. It’s hard to build the high performance teams that we all seek when we have frequently changing membership.

As with any set of measures, I think the value isn’t so much in the number as the signal regarding what to look at in our teams. In addition, I suspect some high performing teams will probably be doing things that don’t show up well in the larger dataset. For instance, I’ve seen many high performing teams with less WIP than the number of team members. Instead they swarm all work, etc.

The report from Rally is well worth reading, although it’s sixteen pages long. (You will have to give away your email address).

To my friends at Rally, there are many interesting questions to be asked here. If we look only at stable teams – what do we learn about team size? If we look only at mature teams (>1 yr old and stable) – do any of our discoveries around team size and estimation change? What about time to fix defects vs. productivity or quality? What about time to fix defects vs. team size? Story size vs. productivity vs. defects? Distributed teams’ productivity? What about the highest performing teams – what where they doing…? Have you considered releasing your dataset to the rest of the world so we can help you mine it? Two reasons: more eyes will spot more ideas and the Agile ideas have always been developed and evolved in an open fashion. Perhaps you could release with the rule that anything someone else discovers from it has to be shared openly.

Hat tip to Dave Nicolette who first pointed this paper out to me

[1] In the paper this is referred to “Full Scrum” – which is odd since Scrum doesn’t require Estimation at all.

Leave a Reply

What is 8 + 10 ?
Please leave these two fields as-is:
Please do this simple sum so I know you are human:)

There are 101 ways to approach anything.
To find the best way, sometimes you need expert help

What People Say

“Kelly revolutionised the way our digital department operated. A true advocate of agile principles, he quickly improved internal communication within our teams and our internal clients by aligning our business and creating a much enhanced sense of transparency in the decisions the business was making. Kelly also introduced a higher sense of empowerment to the development teams...”


“Kelly’s a leading program director with the ability to take charge from day one and keep strong momentum at both a program and project level driving prioritisation, resourcing and budgeting agendas. Kelly operates with an easy-going style and possesses a strong facilitation skill set. From my 5 months experience working with Kelly, I would recommend Kelly to program manage large scale, complex, cross company change programs both from a business and IT perspective.”


“Kelly is an extremely talented and visionary leader. As such he manages to inspire all around him to achieve their best. He is passionate about agile and has a wealth of experience to bring to bear in this area. If you're 'lucky' he might even tell you all about his agile blog. Above all this, Kelly is great fun to work with. He is always relaxed and never gets stressed - and trust me, he had plenty of opportunity here! If you get the chance to work with Kelly, don't pass it up.”


“Kelly is an Agile heavy-weight. He came in to assess my multi-million $ Agile development program which wasn’t delivering the right throughput. He interviewed most of the team and made some key recommendations that, when implemented, showed immediate results. I couldn’t ask for more than that except he’s a really nice guy as well.”


“Kelly and I worked together on a very large project trying to secure a new Insurer client. Kelly had fantastic commercial awareness as well as his technical expertise. Without him I would never had secured this client so I owe a lot to him. He is also a really great guy!”


“Kelly came to the department and has really made a huge impact on how the department communicates, collaborates and generally gets things done. We were already developing in an agile way, but Kelly has brought us even more into alignment with agile and scrum best practices, being eager to share information and willing to work with us to change our processes rather than dictate how things must be done. He is highly knowledgable about agile development (as his active blog proves) but his blog won't show what a friendly and knowledgeable guy he is. I highly recommend Kelly to anyone looking for a CTO or a seminar on agile/scrum practices - you won't be disappointed!”


“Kelly was a great colleague to work with - highly competent, trustworthy and generally a nice bloke.”


“Kelly was engaged as a Program Director on a complex business and technology transformation program for Suncorp Commercial Insurance. Kelly drew on his key capabilities and depth of experience to bring together disparate parties in a harmonised way, ensuring the initiate and concept phases of the program were understood and well formulated. Excellent outcome in a very short time frame. ”


“I worked with Kelly on many projects at IPC and I was always impressed with his approach to all of them, always ensuring the most commercially viable route was taken. He is great at managing relationships and it was always a pleasure working with him.”


“I worked with Kelly whilst at Thoughtworks and found him to be a most inspiring individual, his common-sense approach coupled with a deep understanding of Agile and business makes him an invaluable asset to any organisation. I can't recommend Kelly enough.”


“Kelly was a brilliant CTO and a great support to me in the time we worked together. I owe Kelly a great deal in terms of direction and how to get things done under sometimes difficult circumstances. Thanks Kelly.”