Why is 3 the low limit for Scrum and not 2 ?

Last post 03:08 am September 19, 2019
by Daniel Wilhite
3 replies
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08:26 am September 18, 2019

Hi,
I was wondering why is 3 the low limit for Scrum.
Before I must say that I fully agree that by construction if the limit is 3, so by "making Scrum with 2 people" it won't be Scrum.
But I can't understand why the limit of 3 has been chosen.

Is it complexity? 
Because if I compare a team of 3 working on a 2-3 month Web Application (small e commerce site), with 2 people working for 7-8 month on another Web App.
As I am currently working in a services company of 100 people, both models could be used to do a mission.

I would say that on the paper the team of 2 would have more complexity to do.
with 2 people, there can be 1 PO, 1 SM, who are part of the Dev team like in a team of 3. In both cases the team have the skills to deliver increment.
All the events can be made.  

Someone asked me and apart from "it is on the Scrum Guide", I said that maybe 2 wasn't complex enough in term of human problems, but I wasn't sure. 
Anyone could help me ?

 

02:25 pm September 18, 2019

Hello Laurent, the 3 - 9 is guidance, not a must. You can do Scrum with 1 or 2 people.  

05:04 pm September 18, 2019

Eric Naiburg is right - the size of a team in Scrum is not a hard limit.

However, consider the Scrum events and artifacts and what happens when you have 2 people. Consider a specific example - does a Daily Scrum add value when it's so easy for 2 people to communicate and have a good understanding of what each other is doing or any impediments? I'd argue no. The Daily Scrum, as it's defined in the Scrum Guide, is good for getting a small group of people informed on the current state of progress, aligned, and any replanning done, but it's overhead for 2 people. The moment you remove this event, though, what you have is no longer Scrum.

There may be lessons that can be learned from Scrum, but when your team is too small, the things that are designed to improve communication just add unnecessary overhead that slows down progress.

03:08 am September 19, 2019

I would say that on the paper the team of 2 would have more complexity to do.
with 2 people, there can be 1 PO, 1 SM, who are part of the Dev team like in a team of 3. In both cases the team have the skills to deliver increment.

I may be misunderstanding you but are you saying that the PO and SM are also part of the Development Team?  Because I have encountered problems with this when people try to split their time between roles they usually will dedicate more time to the role they enjoy. And I have never met a developer that liked doing Product Owner or Scrum Master duties. But that is for another discussion.

My opinion is that the 3 person guidance is based on studies done of team size. There are many studies that say 5 is the optimum number for an effective team.  Take into account that a Scrum Team will have a Product Owner (team member #1) and a Scrum Master (Team member #2) having 3 developers (Team member #3, #4, #5) makes up an optimal effective team. If a team is 2 people it can be difficult to arrive at decisions because there can be no majority.  I know agile is about team decisions but if 2 people completely disagree how does the team move forward? With 3 people you can have a simple majority.  If you get too large of a team it becomes even more difficult to arrive at consensus. Since the Development Team is responsible for the decisions made on how to actually implement a solution it is important for them to be able to arrive at decisions. And since the team will respect that everyone is doing the right thing, a simple majority can be used to help the team move forward.