I’m asked a lot about the size of a Scrum Team – they want to know the ideal number of people for one Scrum Team. According to the Scrum Guide, a Scrum Team should have one Product Owner, one ScrumMaster, and up to 10 developers. If you’re a ScrumMaster and you’re also a developer, it counts as one developer. If you’re a Product Owner who’s also a developer, that counts as one developer. So if you’re on a Scrum Team where the ScrumMaster and Product Owner are both developers, then you can only add 8 more developers and your Scrum Team will be at capacity.
But maybe a more important question is: what causes any number of people to become “too many” people? Numerous studies performed over the years have proven that as more people are added to a team, some negative side effects surface. If the byproducts of “too many” on a Scrum Team are unfavorable, we want to avoid that by all means. The Scrum Guide may say 10 developers on a Scrum Team is ideal, but many studies show that the “sweet spot” tends to be around 4 or 5.
Why is that? Well, by adding more people to a team, you may think you’re reducing development time or improving product quality, but adding people to the team also increases the “load” on other things, like process overhead and communications overhead, and it increases how complex it is to keep everybody on the same page at the same time.
It can also introduce what some call “motivational deficit,” meaning that each individual person on the team is more likely to work less diligently. This is basic human psychology – if you’re one of a 2-person team, it’s pretty clear who’s responsible when something doesn’t get done. But if you’re one of a 10-person team, there’s much less accountability.
Of course, in the big picture, it doesn’t really matter which individual team member is responsible for something going sideways – I tell all the teams I coach and train that trying to figure out who’s responsible for a missed deadline isn’t even worth the effort. If “the team” missed a deadline, then “the team” is responsible, period. But the reality is that accountability IS a motivator, and studies show that each individual team member will begin to contribute a little less with each person that’s added to the team.
With so many studies proving smaller numbers are better, why would the Scrum Guide recommendation be 10? Because Scrum grew up in Information Technology, an industry where the work is very complex and requires a wide variety of skills, and each of those skills has a learning curve that’s quite steep. An Information Technology Scrum team may NEED to have this many people just to cover all the skills needed. Remember: when staffing a Scrum Team, you’ve got to have ALL the skills needed to go from concept to customer.
So how many is too many? For YOU, the ideal number may be 4, or it could be 6, or it may actually be 10! In summary, smaller teams are better in most cases. It’s better to have more smaller teams than to have fewer bigger teams. Although it may seem counterintuitive, trust me, that’s the way to go.
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